Hi guys,
I have a question about estimation, when we want to estimating when subtracting or adding, why in some questions, the solution is to round numbers to nearest 10 but in some other cases the solution is to round to nearest 100?
and what about this case? one number is rounded to nearest 10 but the other one to nearest 100
First we must understand why we have to round. : We do this to facilitate mental calculations, this is to estimate a quantity. Now continuing with the question, when are we going to round to the nearest ten? It refers to whether we are going to make a sum where the ten of such a number becomes difficult to add or estimate. What we do is round to make it easier, but for this sum to be as close to the exact number as possible, we must follow some rules that are the following: if the ten is for a number greater than or equal to 5 in the positional value of the one, example 15, its unit is 5, then the nearest ten would be 20, but if the ten has a place value of its smallest unit, for example 14, its nearest ten would be 10, so 14 is rounded to 10.
This also happens with hundreds, but the difference is that the place value that influences whether the rounding increases or decreases would be in its place value of the tens, that is, if we have 151, the value would be rounded to 200 because its ten is greater than 4, that is, it is 5. Otherwise, if it were 141, it would be rounded to 100 because its value is less than 5, and so on.
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