Estimation

Front

What is estimation?

Back

Estimation is a way to find an approximate value or answer, rather than an exact one.

Front

Why do we use estimation?

Back

We use estimation to make quick calculations and to check if our answers are reasonable.

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

Estimate the sum of 13 and 28 by rounding.

Back

Round 13 to 10 and 28 to 30. The estimated sum is 10 + 30 = 40.

Front

What is the estimated total of 231 and 392?

Back

Round 231 to 230 and 392 to 400. The estimated total is 230 + 400 = 630.

Front

How do you find the difference between two numbers using estimation?

Back

Round each number to the nearest ten and then subtract the smaller from the larger.

Front

Estimate how many more students were picked up in the morning than in the afternoon if 176 were picked up in the morning and 84 in the afternoon.

Back

Round 176 to 180 and 84 to 80. The estimated difference is 180 - 80 = 100.

Front

What is the estimated difference between 344 and 452 when rounded to the nearest ten?

Back

Round 344 to 340 and 452 to 450. The estimated difference is 340 - 450 = -110.

Front

Which number sentence shows the best estimate of the total number of coins: 350+180+40 or 360+140+80?

Back

360+140+80=580 is the best estimate.

Front

What is a quick way to check if an answer is reasonable?

Back

Use estimation to see if the answer is close to what you expect.