Estimating Sums and Differences

Front

What is estimating sums?

Back

Estimating sums means finding a close value to the actual sum by rounding numbers before adding them.

Front

What is estimating differences?

Back

Estimating differences means finding a close value to the actual difference by rounding numbers before subtracting them.

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

What is the sum of 17 and 29?

Back

The sum is 46.

Front

If Sally has $50 and buys a shirt for $17 and pants for $29, how much money does she have left?

Back

Sally has $4 left.

Front

What is the total number of cars Becca counted?

Back

Becca counted 148 red cars and 153 blue cars, totaling 301 cars.

Front

What is the total number of cars Jasmine counted?

Back

Jasmine counted 184 white cars and 92 green cars, totaling 276 cars.

Front

How do you find out who counted more cars?

Back

Compare the total counts after rounding to the nearest ten.

Front

What is the difference in pumpkin seeds counted by Brita and her mom compared to Max and his dad?

Back

Brita and her mom counted 333 seeds, while Max and his dad counted 243 seeds. The difference is 90 seeds.

Front

What is the total number of works of art in the museum?

Back

The total is 805 works of art (237 + 349 + 219).