Problem: Estimation and Rounding
The task is to estimate each sum or difference by rounding to the nearest ten. Let's solve each problem step by step.
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Problem 1:
Bria baked 155 cupcakes for the bake sale. She sold 75 of them. Estimate how many cupcakes she sold.
Solution:
- The number of cupcakes sold is already given as 75.
- To round 75 to the nearest ten:
- 75 is exactly halfway between 70 and 80.
- By convention, we round up when the number is exactly halfway.
- Therefore, 75 rounds to 80.
Answer:
$$
\boxed{80}
$$
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Problem 2:
There were lots of people at the baseball game yesterday. 248 of them wore red and 322 of them wore blue to support their team. Estimate how many people were at the baseball game altogether.
Solution:
- First, round 248 to the nearest ten:
- 248 is closer to 250 than to 240.
- Therefore, 248 rounds to 250.
- Next, round 322 to the nearest ten:
- 322 is closer to 320 than to 330.
- Therefore, 322 rounds to 320.
- Now, add the rounded numbers:
$$
250 + 320 = 570
$$
Answer:
$$
\boxed{570}
$$
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Problem 3:
There were 289 cars in the parking lot at the mall on Monday morning. By 12:00, 113 of them were gone. Estimate how many cars were left in the parking lot.
Solution:
- First, round 289 to the nearest ten:
- 289 is closer to 290 than to 280.
- Therefore, 289 rounds to 290.
- Next, round 113 to the nearest ten:
- 113 is closer to 110 than to 120.
- Therefore, 113 rounds to 110.
- Now, subtract the rounded numbers:
$$
290 - 110 = 180
$$
Answer:
$$
\boxed{180}
$$
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Problem 4:
Jesse drove 345 miles on Friday and 219 miles on Saturday to get to the family reunion. Estimate how many miles Jesse traveled in all.
Solution:
- First, round 345 to the nearest ten:
- 345 is closer to 350 than to 340.
- Therefore, 345 rounds to 350.
- Next, round 219 to the nearest ten:
- 219 is closer to 220 than to 210.
- Therefore, 219 rounds to 220.
- Now, add the rounded numbers:
$$
350 + 220 = 570
$$
Answer:
$$
\boxed{570}
$$
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Problem 5:
There are 2,366 books in the library. By the end of the week, 1,321 are on loan to the students. Estimate how many books are not on loan.
Solution:
- First, round 2,366 to the nearest ten:
- 2,366 is closer to 2,370 than to 2,360.
- Therefore, 2,366 rounds to 2,370.
- Next, round 1,321 to the nearest ten:
- 1,321 is closer to 1,320 than to 1,330.
- Therefore, 1,321 rounds to 1,320.
- Now, subtract the rounded numbers:
$$
2,370 - 1,320 = 1,050
$$
Answer:
$$
\boxed{1050}
$$
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Final Answers:
1. $\boxed{80}$
2. $\boxed{570}$
3. $\boxed{180}$
4. $\boxed{570}$
5. $\boxed{1050}$
Parent Tip: Review the logic above to help your child master the concept of estimating word problems worksheet.
