Rounding and Estimation for Addition and Subtraction

Front

What is rounding in mathematics?

Back

Rounding is the process of adjusting the digits of a number to make it simpler while keeping its value close to what it was. It often involves increasing or decreasing the number to the nearest specified place value.

Front

How do you round a number to the nearest hundred?

Back

To round a number to the nearest hundred, look at the digit in the tens place. If it is 5 or greater, round up; if it is 4 or less, round down.

Front

What is the result of rounding 149 to the nearest hundred?

Back

149 rounded to the nearest hundred is 100.

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 greater, round up; if it is 4 or less, round down.

Front

What is the result of rounding 752 to the nearest ten?

Back

752 rounded to the nearest ten is 750.

Front

Which number does NOT round to 400 when rounding to the nearest hundred?

Back

345 does NOT round to 400 when rounding to the nearest hundred.

Front

How do you round a number to the nearest ten and hundred simultaneously?

Back

To round a number to the nearest ten and hundred, first round to the nearest ten, then round the result to the nearest hundred.

Front

What is the result of rounding 254 to the nearest ten and hundred?

Back

254 rounded to the nearest ten is 250, and rounded to the nearest hundred is 300.

Front

How do you estimate the result of a subtraction problem using rounding?

Back

To estimate the result of a subtraction problem using rounding, round both numbers to the nearest specified place value and then perform the subtraction.

Front

Estimate the result of 2,252 - 198 by rounding to the nearest hundred.

Back

2,252 rounds to 2,300 and 198 rounds to 200, so the estimated result is 2,300 - 200 = 2,100.