Estimating Sums and Differences

Front

What is the process of estimating sums and differences in mathematics?

Back

Estimating sums and differences involves rounding numbers to the nearest ten, hundred, or other place value to simplify calculations and make them easier to perform mentally.

Front

How do you estimate the sum of two numbers?

Back

To estimate the sum, round each number to the nearest ten or hundred and then add the rounded numbers together.

Front

How do you estimate the difference between two numbers?

Back

To estimate the difference, round each number to the nearest ten or hundred and then subtract the smaller rounded number from the larger rounded number.

Front

What is the estimated sum of 798 and 205?

Back

The estimated sum is 800 + 200 = 1000.

Front

What is the estimated difference of 850 and 320?

Back

The estimated difference is 900 - 300 = 600.

Front

Why is estimating sums and differences useful?

Back

Estimating sums and differences is useful for quickly checking calculations, making decisions, and understanding the magnitude of numbers without needing exact values.

Front

What is rounding in the context of estimation?

Back

Rounding is the process of adjusting a number to a nearby specified value, often to make calculations simpler.

Front

What is the estimated sum of 499 and 299?

Back

The estimated sum is 500 + 300 = 800.

Front

What is the estimated difference of 750 and 450?

Back

The estimated difference is 800 - 500 = 300.

Front

How can you check the reasonableness of your estimated sum?

Back

You can check the reasonableness by comparing the estimated sum to the actual sum and ensuring it falls within a reasonable range.