Estimating Sums and Differences

Front

What is estimating sums?

Back

Estimating sums means finding a close value to the actual sum of two or more numbers without calculating the exact total.

Front

What is estimating differences?

Back

Estimating differences means finding a close value to the actual difference between two numbers without calculating the exact result.

Front

How do you round a number to the nearest ten?

Back

Look at the digit in the ones place. If it's 5 or more, round up. If it's 4 or less, round down.

Front

How do you round a number to the nearest hundred?

Back

Look at the digit in the tens place. If it's 5 or more, round up. If it's 4 or less, round down.

Front

What is the estimated sum of 32 and 16?

Back

The estimated sum is 50 minutes.

Front

If you have $50 and spend $17 on a shirt and $29 on pants, do you have enough money?

Back

Yes, you have enough money.

Front

What is the estimated sum of 123 and 456 when rounded to the nearest hundred?

Back

The estimated sum is 600.

Front

If you have 819, what is the approximate value when rounded to the nearest hundred?

Back

The approximate value is 820.

Front

If you have 382, what is the approximate value when rounded to the nearest hundred?

Back

The approximate value is 400.

Front

What is a reasonable estimate for the sum of 48 and 27?

Back

A reasonable estimate is 70.