Estimate Decimal Sums and Differences

Estimate the difference by rounding each number to the nearest whole number and then subtracting.

5.104 − 1.972

The difference is approximately

Estimate the difference by rounding each number to the nearest whole number and then subtracting.

10.477 − 3.316

The difference is approximately

Estimate the difference by rounding each number to the nearest whole number and then subtracting.

7.096 − 4.774

The difference is approximately

Estimate the sum by rounding each number to the nearest whole number and then adding.

10.17 + 5.13 + 2.6

The sum is approximately

Connect Geoff and Andrea want to combine their money to buy pizza. Geoff has $5.95. Andrea has $8.30. Which benchmarks should they use to estimate the money they have?

• $6.00 + $8.25

• $5.75 + $8.00

• $6.00 + $8.50

• $5.00 + $8.00

Multi-Step Maiko wrote two songs. The first song was 2.9 minutes long. Then he added 0.4 minute. The second song was 5.6 minutes long. Then he subtracted 1.1 minutes from it. Use benchmarks to estimate the length of each song.

• first song: 2.5 minutes, second song: 4 minutes

• first song: 3.5 minutes, second song: 4.5 minutes

• first song: 3.5 minutes, second song: 7 minutes

• first song: 2.5 minutes, second song: 5.5 minutes

Fran bought sneakers for $54.26 and a shirt for $34.34. If Fran started with $100, about how much money does she have left?

• $35

• $20

• $5

• $80

Mike spends $23.40 on a present for his mom and a $18.95 on a present for his dad. If Mike started with $75, about how much money does he have left?

• $30

• $50

• $20

• $40

Jesse, Max, and Kalel each ate 0.32 of a pizza pie. Which number shows the best estimate of how much of the pie they ate together?

• 1.0

• 0.5

• 0.25

• 0.10

George is giving two speeches at school. The first was 3.4 minutes long. Then he added 0.9 minutes to the speech. The second speech was 4.1 minutes long. Then he subtracted 1.4 minutes from it. Use benchmarks to estimate the length of each speech.

• first speech: 4.0 minutes; second speech: 3.5 minutes

• first speech: 4.0 minutes; second speech: 3 minutes

• first speech: 4.5 minutes; second speech: 2.5 minutes

• first speech: 4.5 minutes; second speech: 3.5 minutes