1.5. Estimation of Whole Number Addition and Subtraction

Front

What is estimation in the context of addition and subtraction?

Back

Estimation means to find an answer that is close to the exact answer, used in instances that don’t require an exact answer.

Front

What is the first step in estimating a sum or a difference?

Back

The first step is to round the numbers to the nearest power of ten, hundred, thousand, etc.

Front

What should you do after rounding the numbers for estimation?

Back

Use mental math to estimate an answer.

Front

What are the two types of problems you can estimate?

Back

You can estimate sums (addition problems) and differences (subtraction problems).

Front

What is the rounding rule for numbers less than 5?

Back

If the number being rounded is less than 5, round down.