Question

use the three - reads strategy to help understand the word problem. solve each word problem by estimating the sum. then find the sum.

1. dante’s family donated 105.652 pounds of food to the local food drive. terrance’s family donated 98.48 pounds of food to the local food drive. round to the nearest tenth to find the estimated sum of the donations, then solve. show all work.
2. marissa runs three 200 - meter races. she completes her first race in 45.485 seconds. she completes her second race in 49.625 seconds. she completes her final race in 47.862 seconds. round to the nearest whole number to find the estimated sum of her times, then solve. show all work.

Explanation:

Problem 4

Step1: Round each number to nearest tenth

Dante's family: \(105.652\) rounded to nearest tenth is \(105.7\) (since the hundredth digit is 5, we round up the tenth digit).
Terrance's family: \(96.48\) rounded to nearest tenth is \(96.5\) (since the hundredth digit is 8, which is ≥5, we round up the tenth digit).

Step2: Find estimated sum

Add the rounded numbers: \(105.7 + 96.5 = 202.2\)

Step3: Find actual sum

Add the original numbers: \(105.652 + 96.48 = 202.132\)

Problem 5

Step1: Round each time to nearest whole number

First race: \(45.485\) rounded to nearest whole number is \(45\) (since the tenth digit is 4, which is <5, we round down).
Second race: \(49.625\) rounded to nearest whole number is \(50\) (since the tenth digit is 6, which is ≥5, we round up).
Final race: \(47.862\) rounded to nearest whole number is \(48\) (since the tenth digit is 8, which is ≥5, we round up).

Step2: Find estimated sum

Add the rounded times: \(45 + 50 + 48 = 143\)

Step3: Find actual sum

Add the original times: \(45.485 + 49.625 + 47.862 = 142.972\)

Answer:

s:

Problem 4

• Estimated sum: \(202.2\) pounds
• Actual sum: \(202.132\) pounds

Problem 5

• Estimated sum: \(143\) seconds
• Actual sum: \(142.972\) seconds