Rounding to Add & Subtract

Front

What is rounding?

Back

Rounding is the process of adjusting a number to make it simpler and easier to work with, usually to the nearest ten, hundred, or other place value.

Front

How do you round a number to the nearest ten?

Back

To round a number to the nearest ten, look at the digit in the ones place. If it is 5 or more, round up. If it is 4 or less, round down.

Front

Estimate the sum of 45 + 76 by rounding to the nearest ten.

Back

50 + 80 = 130.

Front

Estimate the sum of 753 + 142 by rounding to the nearest hundred.

Back

800 + 100 = 900.

Front

What is the best estimate of the total number of items if Tracy ordered 325 pet toys and 165 bags of dog food?

Back

500.

Front

How do you find the total number of items using estimation?

Back

Round each number to the nearest ten or hundred, then add the rounded numbers.

Front

A museum has 237 works of art on the first floor, 349 on the second, and 219 on the third. Estimate the total number of works of art.

Back

700.

Front

What is 104 rounded to the nearest ten?

Back

100.

Front

What is the greatest place value?

Back

The greatest place value is the highest value position in a number, such as hundreds, tens, or units.

Front

Why is estimation useful in addition and subtraction?

Back

Estimation helps to quickly find an approximate answer without needing exact calculations.