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Course Updates for Pre-Algebra in July 2021

Updated

We are excited to share that we've made significant enhancements to our Pre-Algebra. One consequence of adding this new content is that it may impact learners’ Mastery percentages.

When we add new content and remove old content, Mastery percentages often change because the number of available skills changes. For example, if you mastered 90 out of 100 skills in a course, and we added 10 new skills, your mastery skill count would then be 90 out of 110. This change would change your Mastery percentage from 90% to 82%.

With this specific course update, we expect that Mastery percentages will change by a maximum of 61%. Most people will see a much smaller Mastery percentage change.

You can see exactly what content items we’ve added and removed below. Happy learning! 

Content Added

Articles

Factors and multiples

Finding mistakes in one-step equations

Graphing lines from slope-intercept form review

Graphing slope-intercept form

Intercepts of lines review (x-intercepts and y-intercepts)

Intro to slope

Intro to slope-intercept form

Modeling with tables, equations, and graphs

Multi-step equations review

Multi-step ratio and percent problems

One-step inequalities review

Order of operations review

Slope formula

Slope review

Slope-intercept form review

Substitution method review (systems of equations)

Systems of equations with graphing

Systems of equations with substitution

Terms, factors, and coefficients review

Writing slope-intercept equations

Exercises

Adding & subtracting in scientific notation

Approximating with powers of 10

Combining like terms

Combining like terms with negative coefficients

Combining like terms with negative coefficients & distribution

Combining like terms with rational coefficients

Compare linear functions

Comparing linear functions word problems

Complete solutions to 2-variable equations

Constant of proportionality from tables

Create equivalent expressions by factoring

Distributive property with variables

Distributive property with variables (negative numbers)

Equations with parentheses

Equations with parentheses: decimals & fractions

Equations with square roots & cube roots

Equations with square roots: decimals & fractions

Equations with variables on both sides

Equations with variables on both sides: decimals & fractions

Equivalent expressions

Equivalent expressions: negative numbers & distribution

Evaluate functions

Evaluate functions from their graph

Factor with distributive property (variables)

Find the mistake in one-step equations

Find the mistake: two-step equations

Function rules from equations

Graph from slope-intercept form

Graphing basic inequalities

Graphing linear relationships word problems

Graphing proportional relationships

Identify proportional relationships from graphs

Intercepts from a graph

Intercepts from an equation

Interpret two-step equation word problems

Interpreting graphs of functions

Interpreting graphs of proportional relationships

Interpreting linear expressions

Linear & nonlinear functions

Linear equations word problems

Linear equations word problems: graphs

Linear models word problems

Number of solutions to equations

Number of solutions to equations challenge

One-step inequalities

Order of operations (no exponents)

Order of operations challenge

Parts of algebraic expressions

Patterns with shapes

Powers of fractions

Rates & proportional relationships

Rates with fractions

Recognize functions from graphs

Recognize functions from tables

Roots of decimals & fractions

Scientific notation word problems

Slope from equation

Slope from graph

Slope from two points

Slope-intercept equation from graph

Slope-intercept from two points

Slope-intercept intro

Solutions of systems of equations

Solutions to 2-variable equations

Square and cube challenge

Sums of consecutive integers

Systems of equations with graphing

Systems of equations with substitution

Testing solutions to inequalities

Testing solutions to inequalities (basic)

Two-step equations with decimals and fractions

Two-step equations word problems

Two-step inequalities

Two-step inequality word problems

Writing linear functions word problems

Writing proportional equations

Writing proportional equations from tables

Videos

Approximating with powers of 10

Checking if a table represents a function

Checking if an equation represents a function

Combining like terms

Combining like terms example

Combining like terms with negative coefficients

Combining like terms with negative coefficients & distribution

Combining like terms with rational coefficients

Comparing constants of proportionality

Comparing linear functions word problem: climb

Comparing linear functions word problem: walk

Comparing linear functions word problem: work

Comparing linear functions: equation vs. graph

Comparing linear functions: faster rate of change

Comparing linear functions: same rate of change

Completing solutions to 2-variable equations

Constant of proportionality from graph

Constant of proportionality from tables

Converting to slope-intercept form

Creating an equation with infinitely many solutions

Creating an equation with no solutions

Dimensions of a cube from its volume

Distributive property with variables

Does a vertical line represent a function?

Equation with the variable in the denominator

Equation with variables on both sides: fractions

Equations for proportional relationships

Equations vs. functions

Equations with parentheses

Equations with variables on both sides: 20-7x=6x-6

Equivalent expressions

Equivalent expressions: negative numbers & distribution

Factoring with the distributive property

Find the mistake: two-step equations

Finding mistakes in one-step equations

Fitting a line to data

Function notation example

Graph from slope-intercept equation

Graphing proportional relationships from a table

Graphing proportional relationships from an equation

Graphing proportional relationships: unit rate

Graphing sequence relationships

Identifying proportional relationships from graphs

Identifying the constant of proportionality from equation

Inequalities word problems

Intercepts from a table

Intercepts from an equation

Interpreting a graph example

Interpreting graphs of proportional relationships

Interpreting linear expressions: diamonds

Interpreting linear expressions: flowers

Intro to combining like terms

Intro to equations with variables on both sides

Intro to intercepts

Intro to slope

Intro to slope-intercept form

Intro to the coordinate plane

Introduction to proportional relationships

Is side length & area proportional?

Is side length & perimeter proportional?

Linear & nonlinear functions: missing value

Linear & nonlinear functions: table

Linear & nonlinear functions: word problem

Linear equations word problems: earnings

Linear equations word problems: volcano

Linear function example: spending money

Linear functions word problem: fuel

Linear functions word problem: iceberg

Linear functions word problem: paint

Linear functions word problem: pool

Linear graphs word problem: cats

Linear graphs word problems

Manipulating formulas: temperature

Modeling with linear equations: gym membership & lemonade

Modeling with linear equations: snow

Number of solutions to equations

Obtaining a function from an equation

One-step inequalities examples

One-step inequalities: -5c ≤ 15

One-step inequality word problem

Order of operations example

Positive & negative slope

Powers of fractions

Proportional relationships: graphs

Rate problems

Rates & proportional relationships example

Rates & proportional relationships: gas mileage

Rates with fractions

Rational number word problem: checking account

Rational number word problem: computers

Rational number word problem: ice

Rational number word problem: stock

Recognizing functions from graph

Recognizing functions from table

Recognizing functions from verbal description

Recognizing functions from verbal description word problem

Recognizing linear functions

Relations and functions

Scientific notation word problem: U.S. national debt

Scientific notation word problem: red blood cells

Scientific notation word problem: speed of light

Simplifying in scientific notation challenge

Slope & direction of a line

Slope from equation

Slope of a horizontal line

Slope of a line: negative slope

Slope-intercept equation from graph

Slope-intercept equation from slope & point

Slope-intercept equation from two points

Slope-intercept form from a table

Slope-intercept form problems

Solutions to 2-variable equations

Square root of decimal

Subtracting in scientific notation

Sum of integers challenge

Sums of consecutive integers

Systems of equations with graphing

Systems of equations with graphing: 5x+3y=7 & 3x-2y=8

Systems of equations with graphing: chores

Systems of equations with graphing: exact & approximate solutions

Systems of equations with graphing: y=7/5x-5 & y=3/5x-1

Systems of equations with substitution: -3x-4y=-2 & y=2x-5

Systems of equations with substitution: 2y=x+7 & x=y-4

Systems of equations with substitution: 9x+3y=15 & y-x=5

Systems of equations with substitution: y=-1/4x+100 & y=-1/4x+120

Systems of equations with substitution: y=-5x+8 & 10x+2y=-2

Systems of equations with substitution: y=4x-17.5 & y+2x=6.5

Systems of equations: trolls, tolls (1 of 2)

Systems of equations: trolls, tolls (2 of 2)

Terms, factors, & coefficients

Testing a solution to a system of equations

Testing if a relationship is a function

Testing solutions to inequalities

The distributive property with variables

The zeroth power

Translating expressions with parentheses

Two-step equation word problem: computers

Two-step equation word problem: garden

Two-step equation word problem: oranges

Two-step equations with decimals and fractions

Two-step equations with decimals and fractions

Two-step inequalities

Two-step inequality word problem: R&B

Two-step inequality word problem: apples

What is a function?

Worked example: Evaluating functions from equation

Worked example: Evaluating functions from graph

Worked example: Order of operations (PEMDAS)

Worked example: intercepts from an equation

Worked example: number of solutions to equations

Worked example: slope from graph

Worked example: slope from two points

Worked example: solutions to 2-variable equations

Worked examples: slope-intercept intro

Writing proportional equations

Writing proportional equations from tables

x-intercept of a line

 

Content Removed

Articles

Absolute value review

Adding decimals

Adding negative numbers review

Associative property of multiplication review

Classifying numbers review

Common denominators review

Commutative property of multiplication review

Comparing fractions review

Coordinate plane parts review

Decimal place value review

Decimals in expanded form review

Decimals in written form review

Decomposing fractions review

Distributive property explained

Distributive property review

Dividing decimals

Dividing fractions review

Dividing negative numbers review

Equivalent fractions review

Factors and multiples review

Graphing coordinates review

Intro to absolute value

Intro to negative numbers

Mixed numbers and improper fractions review

Multiplying decimals (no standard algorithm)

Multiplying fractions review

Multiplying negative numbers review

Number opposites

Number opposites review

One-step equations review

Ordering negative numbers

Points on the coordinate plane

Properties of addition

Properties of multiplication

Subtracting decimals

Subtracting negative numbers review

Whole number place value review

Whole numbers in expanded form review

Whole numbers in written form review

Writing decimals as fractions review

Writing fractions as decimals review

Exercises

2-step expressions

Absolute value to find distance

Add and subtract fractions word problems

Add and subtract fractions word problems (same denominator)

Add and subtract mixed numbers (no regrouping)

Add and subtract mixed numbers with unlike denominators (no regrouping)

Add and subtract mixed numbers with unlike denominators (regrouping)

Add fractions with common denominators

Add fractions with unlike denominators

Adding & subtracting decimals word problems

Adding & subtracting negative numbers

Adding decimals: hundredths

Adding decimals: tenths

Adding decimals: thousandths

Adding negative numbers

Approximating square roots

Area & perimeter of rectangles word problems

Associative property of multiplication

Classify numbers: rational & irrational

Common denominators

Commutative property of multiplication

Compare 2-digit numbers

Compare and order absolute values

Compare decimal place value

Compare decimals (tenths and hundredths)

Compare decimals through thousandths

Compare fractions and mixed numbers

Compare fractions on the number line

Compare fractions using benchmark

Compare fractions with different numerators and denominators

Compare fractions with the same numerator or denominator

Compare fractions word problems

Comparing data displays

Converting fractions to decimals

Coordinate plane problems in all four quadrants

Create bar graphs

Create rectangles with a given area

Cut shapes into equal parts

Data set warm-up

Decimals in expanded form

Decimals in words

Decimals in written and expanded form

Decimals on the number line: hundredths

Decimals on the number line: tenths

Decimals on the number line: thousandths

Decompose fractions

Decompose fractions visually

Distance between points: vertical or horizontal

Distributive property

Divide fractions and whole numbers word problems

Divide mixed numbers

Dividing decimals 1

Dividing decimals 2

Dividing decimals: hundredths

Dividing decimals: thousandths

Dividing fractions

Dividing fractions word problems

Dividing negative numbers

Dividing unit fractions by whole numbers

Dividing whole numbers by unit fractions

Dividing whole numbers like 56÷35 to get a decimal

Divisibility tests

Equivalent fractions

Equivalent fractions

Equivalent fractions (fraction models)

Equivalent fractions (number lines)

Factor with the distributive property (no variables)

Find a missing side length when given perimeter

Find area by counting unit squares

Find area with partial unit squares

Find perimeter by counting units

Find perimeter when given side lengths

Finding absolute values

Fraction multiplication as scaling

Fractions as division

Fractions greater than 1 on the number line

Fractions in contexts

Fractions on the number line

GCF & LCM word problems

Greatest common factor

Identify points on a line

Identify value of a digit

Interpreting negative numbers

Least common multiple

Multiply fractions and whole numbers

Multiply fractions and whole numbers on the number line

Multiply fractions and whole numbers with fraction models

Multiply fractions word problems

Multiply mixed numbers

Multiply mixed numbers and whole numbers

Multiplying decimals like 0.847x3.54 (standard algorithm)

Multiplying decimals like 2.45x3.6 (standard algorithm)

Multiplying decimals like 4x0.6 (standard algorithm)

Multiplying fractions

Multiplying fractions with visuals

Multiplying negative numbers

Negative numbers on the number line

Number opposites

Order decimals

Order decimals and fractions in different forms

Order fractions

Ordering negative numbers

Place value tables

Place value when multiplying and dividing by 10

Points on the coordinate plane

Powers of products & quotients (structured practice)

Prime factorization

Properties of exponents challenge (integer exponents)

Quadrants on the coordinate plane

Rate problems 2

Read bar graphs (2-step problems)

Read histograms

Read picture graphs (multi-step problems)

Reading dot plots & frequency tables

Reading stem and leaf plots

Recognize fractions

Reflecting points in the coordinate plane

Regroup whole numbers

Relate decimals and fractions in words

Relate number lines to fraction bars

Represent rectangle measurements

Represent the commutative property of multiplication

Rewriting decimals as fractions challenge

Round decimals

Round decimals challenge

Round decimals using a number line

Round whole numbers

Signs of expressions

Simplify fractions

Simplify square roots

Subtract fractions with common denominators

Subtracting decimals: hundredths

Subtracting decimals: tenths

Subtracting decimals: thousandths

Subtracting fractions with unlike denominators

Subtracting negative numbers

Transition from unit squares to area formula

Understand associative property of multiplication

Understand multiplying by a multiple of 10, 100, and 1000

Understand numerators and denominators

Understand subtraction as adding the opposite

Understand the commutative property of multiplication

Unit fractions on the number line

Use associative property to multiply 2-digit numbers by 1-digit

Using units to solve problems

Visualize distributive property

Visually add and subtract fractions

Volume of rectangular prisms

Volume of rectangular prisms with unit cubes

Volume word problems

Write common fractions as decimals

Write decimals and fractions greater than 1 shown on grids

Write decimals and fractions shown on grids

Write decimals and fractions shown on number lines

Write decimals as fractions

Write fractions as decimals (denominators of 10 & 100)

Write mixed numbers and improper fractions

Write whole numbers in expanded form

Writing numerical inequalities

Videos

1 and -1 to different powers

2-step estimation word problems

Absolute value as distance between numbers

Absolute value examples

Adding & subtracting decimals word problem

Adding & subtracting negative numbers

Adding decimals with ones, tenths and hundredths

Adding decimals word problem

Adding decimals: 0.822+5.65

Adding decimals: 9.087+15.31

Adding fractions with like denominators

Adding fractions with unlike denominators

Adding fractions word problem: paint

Adding mixed numbers with like denominators

Adding mixed numbers with regrouping

Adding mixed numbers: 19 3/18 + 18 2/3

Adding negative numbers example

Adding numbers with different signs

Adding three decimals

Adding whole numbers by their place values

Approximating square roots to hundredths

Area & perimeter word problem: dog pen

Area & perimeter word problem: table

Associative law of addition

Associative law of multiplication

Associative property of multiplication

Classifying numbers: rational & irrational

Common denominators: 1/4 and 5/6

Common denominators: 3/5 and 7/2

Common divisibility examples

Commutative law of addition

Commutative law of multiplication

Commutative property of multiplication

Comparing absolute values

Comparing and ordering fractions

Comparing decimals 2

Comparing decimals 3

Comparing decimals: 156.378 and 156.348

Comparing decimals: 9.97 and 9.798

Comparing dot plots, histograms, and box plots

Comparing fractions

Comparing fractions 2 (unlike denominators)

Comparing fractions with > and < symbols

Comparing fractions with like numerators and denominators

Comparing improper fractions and mixed numbers

Comparing place values

Comparing whole number place values

Converting decimals to fractions 2 (ex 1)

Converting decimals to fractions 2 (ex 2)

Coordinate plane word problem examples

Counting unit squares to find area formula

Creating a bar graph

Creating a fraction through division

Creating rectangles with a given area 1

Creating rectangles with a given area 2

Cube root of a non-perfect cube

Cutting shapes into equal parts

Decimal place value

Decimals as words

Decomposing a fraction visually

Decomposing a mixed number

Developing strategies for multiplying decimals

Distributive property exercise examples

Distributive property when multiplying

Divide whole numbers with decimal quotients: 5÷2

Divide whole numbers with decimal quotients: 78÷12

Dividing by a multi-digit decimal

Dividing decimals completely

Dividing decimals with hundredths

Dividing fractions by whole numbers: studying

Dividing fractions: 2/5 ÷ 7/3

Dividing fractions: 3/5 ÷ 1/2

Dividing positive and negative numbers

Dividing whole numbers & fractions: t-shirts

Dividing whole numbers to get a decimal

Divisibility tests for 2, 3, 4, 5, 6, 9, 10

Division strategies for decimal quotients

Equivalent fraction and whole number multiplication problems

Equivalent fraction models

Equivalent fractions

Exponentiation warmup

Exponents and powers of 10 patterns

Expressing decimals in multiple forms

Finding average speed or rate

Finding common denominators

Finding missing side length when given perimeter

Finding perimeter when a side length is missing

Finding place value

Finding the point not graphed

Fraction to decimal: 11/25

Fraction word problem: lizard

Fraction word problem: piano

Fractions on a number line

Fractions on number line widget

Frequency tables & dot plots

GCF & LCM word problems

Graphing hundredths from 0 to 0.1

Graphing tenths from 0 to 1

Greater than and less than symbols

Greatest common factor examples

Greatest common factor explained

Growing by a percentage

Histograms

Identifying hundredths on a number line

Identifying numerators and denominators

Identifying percent amount and base

Identifying tenths on a number line

Identifying unit fractions word problem

Identity property of 0

Identity property of 1

Inequality word problem: one variable

Inequality word problems

Interpreting bar graphs: alligators

Intro to area and unit squares

Intro to fractions

Intro to multiplying 2 fractions

Intro to multiplying decimals

Intro to negative numbers

Intro to rational & irrational numbers

Introduction to adding decimals: tenths

Introduction to scientific notation

Inverse property of addition

Inverse property of multiplication

Least common multiple

Least common multiple of three numbers

Least common multiple: repeating factors

Long division with decimals

Measuring area with partial unit squares

Measuring rectangles with different unit squares

Measuring volume as area times length

Measuring volume with unit cubes

Misleading line graphs

More advanced subtraction strategies with hundredths

More on equivalent fractions

Multi-digit division strategies for decimals

Multiple rates word problem

Multiple units word problem: road trip

Multiplication as scaling with fractions

Multiplying 2 fractions: 5/6 x 2/3

Multiplying 2 fractions: fraction model

Multiplying 2 fractions: number line

Multiplying challenging decimals

Multiplying decimals using estimation

Multiplying decimals: place value

Multiplying fractions and whole numbers visually

Multiplying fractions word problem: bike

Multiplying fractions word problem: laundry

Multiplying fractions word problem: muffins

Multiplying in scientific notation example

Multiplying mixed numbers

Multiplying positive & negative numbers

Negative symbol as opposite

Number opposites

Order of operations (2-step expressions)

Ordering decimals 1

Ordering decimals 2

Ordering fractions

Ordering negative numbers

Ordering numeric expressions

Orders of magnitude exercise example 1

Orders of magnitude exercise example 2

Percent word problem: 78 is 15% of what number?

Percent word problem: penguins

Perimeter of a shape

Perimeter: introduction

Place value tables

Place value when multiplying and dividing by 10

Place value with decimals

Placing absolute values on the number line

Plotting a point (ordered pair)

Plotting decimal numbers on a number line

Points and quadrants example

Points on the coordinate plane examples

Prime factorization

Prime factorization exercise

Properties and patterns for multiplication

Properties of multiplication

Quadrants of the coordinate plane

Reading bar graphs

Reading pictographs

Reading pie graphs (circle graphs)

Reading stem and leaf plots

Recognize fractions

Recognizing divisibility

Recognizing fractions greater than 1

Reflecting points in the coordinate plane

Regrouping numbers into various place values

Regrouping whole number place values

Regrouping whole numbers: 430

Regrouping whole numbers: 675

Regrouping whole numbers: 76,830

Relating decimals and fractions in words

Representing data

Rewriting decimals as fractions: 0.15

Rewriting decimals as fractions: 0.36

Rewriting decimals as fractions: 0.8

Rounding decimals on the number line

Rounding to the nearest 10 on the number line

Rounding to the nearest 100 on the number line

Rounding whole numbers to nearest hundred

Rounding whole numbers to nearest ten

Rounding whole numbers to nearest thousand

Scientific notation examples

Setting up 2-step word problems

Simplifying a cube root

Simplifying square roots

Solving ratio problems with graph

Speed translation

Stem-and-leaf plots

Strategies for dividing by tenths

Strategies for subtracting more complex decimals with tenths

Subtracting a negative = adding a positive

Subtracting decimals: 39.1 - 0.794

Subtracting decimals: 9.005 - 3.6

Subtracting fractions with like denominators

Subtracting fractions with unlike denominators

Subtracting fractions word problem: tomatoes

Subtracting mixed numbers with like denominators

Subtracting mixed numbers with regrouping (unlike denominators)

Subtracting mixed numbers: 7 6/9 - 3 2/5

The 0 & 1st power

The why of the 3 divisibility rule

The why of the 9 divisibility rule

Thousandths on the number line

Transitioning from unit squares to area formula

Understanding decimal multiplication

Understanding division of fractions

Understanding fractions as division

Understanding place value

Understanding square roots

Using associative property to simplify multiplication

Visual understanding of regrouping decimals

Visualizing equivalent fractions

Visually adding fractions: 5/6+1/4

Visually subtracting fractions: 3/4-5/8

Volume intro

Volume of a rectangular prism

Volume word problem: water tank

Why a negative times a negative is a positive

Why a negative times a negative makes sense

Worked example: Converting a fraction (7/8) to a decimal

Worked example: Rounding decimals to nearest tenth

Write decimal in expanded form

Writing a number as a fraction and decimal

Writing a number in expanded form

Writing a number in standard form

Writing decimal numbers shown in grids

Writing decimals and fractions greater than 1 shown on grids

Writing decimals and fractions shown on number lines

Writing improper fractions as mixed numbers

Writing mixed numbers as improper fractions

Writing numbers in words and standard form