# Math in Focus Grade 5 Chapter 9 Practice 5 Answer Key Estimating Decimals

Practice the problems of Math in Focus Grade 5 Workbook Answer Key Chapter 9 Practice 5 Estimating Decimals to score better marks in the exam.

## Math in Focus Grade 5 Chapter 9 Practice 5 Answer Key Estimating Decimals

Round each decimal to the nearest whole number. Then estimate the sum or difference.

Example
7.7 + 12.3
7.7 rounds to 8.
12.3 rounds to 12.
8 + 12 = 20
7.7 + 12.3 is about 20.

21.8 – 11.5
21.8’ rounds to 22.
11.5 rounds to 12.
22 – 12 = 10
21.8 – 11.5 is about 10.

Question 1.
$2.90 +$7.15
Answer: $10.05 Estimate: 10 Explanation: 2.90 + 7.15 2.90 rounds to 3. 7.15 rounds to 7. 3 + 17 = 10 2.90 + 7.15 is about 10. Question 2. 9.05 + 19.55 Answer:$28.6
Estimate: 29
Explanation:
9.05 + 19.55
9.05 rounds to 9.
19.55 rounds to 20.
9 + 20 = 29
9.05 + 19.55 is about 29.

Question 3.
35.67 – 15.09
Answer: $20.58 Estimate: 21 Explanation: 35.67 – 15.09 35.67 rounds to 36. 15.09 rounds to 15. 36 – 15 = 21 35.67 – 15.09 is about 21. Question 4.$15.40 – $5.95 Answer:$9.45
Estimate: 9
Explanation:
15.40 – 5.95
15.40 rounds to 15.
5.95 rounds to 6.
15 – 6 = 9
15.40 – 5.95 is about 9.

Estimate the product by rounding the decimal to the nearest whole number.

Example
4.5 × 4
4.5 rounds to 5.
5 × 4 = 20
4.5 × 4 is about 20.

Question 5.
19.6 × 3
Estimate: 60
Explanation:
19.6 × 3
19.6 rounds to 20.
20 × 3 = 60
19.6 × 3 is about 60.

Question 6.
0.95 × 8
Estimate:800
Explanation:
0.95 × 8
0.95 rounds to 100.
100 x 8 = 800
0.95 × 8 is about 800.

Question 7.
8.25 × 3
Estimate: 2400
Explanation:
8.25 × 3
8.25 rounds to 800.
800 × 3 = 2400
8.25 × 3 is about 2400.

Estimate the quotient by choosing a whole number close to the dividend that can be evenly divided by the divisor.

Example
24.6 ÷ 5
25 ÷ 5 = 5
24.6 ÷ 5 is about 5.

Question 8.
38.4 ÷ 6
Estimate: 6
Explanation:
38.4 ÷ 6
36 ÷ 6 = 6
38.4 ÷ 6 is about 6.

Question 9.
71.09 ÷ 8
Estimate: 9
Explanation:
71.09 ÷ 8
72 ÷ 8 = 9
71.09 ÷ 8 is about 9.

Question 10.
99.75 ÷ 5
Estimate: 20
Explanation:
99.75 ÷ 5
100 ÷ 5 = 20
99.75 ÷ 5 is about 20.

Round each decimal to the nearest tenth. Then estimate.

Question 11.
0.47 + 15.51
Estimate: 16
Explanation:
0.47 + 15.51
0.47 rounds to 1.
15.51 rounds to 15.
15 + 1 = 16
0.47 + 15.51 is about 16.

Question 12.
9.95 – 1.46
Estimate: 9
Explanation:
9.95 – 1.46
9.95 rounds to 10.
1.46 rounds to 1.
10 – 1 = 9
9.95 – 1.46 is about 9.

Question 13.
2.89 pounds × 4
Estimate: 1200
Explanation:
2.89 × 4
2.89 rounds to 300.
300 × 4 = 1200
2.89 × 4 is about 1200.

Estimate the quotient by choosing a tenth close to the dividend that can be evenly divided by the divisor.

Question 14.
6.34 kilograms ÷ 7
Estimate: 1
Explanation:
6.34 ÷ 7
7 ÷ 7 = 1
6.34 ÷ 7 is about 1.

Question 15.
A bag of walnuts sells for $1.95. Estimate the cost of 8 bags of walnuts. Answer:$15.6
Estimate: 16
Explanation:
1.95 × 8
1.95 rounds to 2.
2 × 8 = 16
1.95 × 8 is about 16.

Question 16.
A piece of plywood is 1 .27 centimeters thick. Find the thickness of a pile of 9 pieces of plywood to the nearest tenth of a centimeter. Estimate to check if your answer is reasonable.