# Course Updates for Pre-Algebra in July 2021

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*

*Exercises*

Combining like terms with negative coefficients & distribution |

Equations with variables on both sides: decimals & fractions |

*Videos*

**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 |