All the solutions provided in McGraw Hill My Math Grade 5 Answer Key PDF Chapter 6 Review will give you a clear idea of the concepts.

Vocabulary Check

Match each word to its definition. Write your answers on the lines provided.

Explanation:
* The Associative Property of Multiplication states that the way in which factors are grouped does not change the product.
* The Commutative Property of Multiplication shows that the order in which factors are multiplied does not change the product.
* The Identity Property of Multiplication states that the product of any factor and 1 equals the factor.
* Compatible numbers are numbers that are easy to multiply mentally.
* Rounding is an estimate or finding an approximate value of a number.
* Numbers like 10, 100, 1000 can be written as Powers of 10.

Concept Check

Estimate each product.

Question 7.
$4.80 × 5 Answer: 25 Explanation: Round up$4.80 to the nearest ten as 5.
If the tenths place is more than 5 round up to the nearest whole number.
5 x 5 = 25
So, 5 × $4.80 = 24 is estimate of 25. Question 8. 3.36 × 4 Answer: 12 Explanation: Round up 3.36 to the nearest ten as 3. If the tenths place is less than 5 round down to the nearest whole number. 3 x 4 = 12 So, 3 × 3.36 = 10.08 is estimate of 12. Question 9. 10.8 × 7 Answer: 77 Explanation: Round up 10.8 to the nearest ten as 11. If the tenths place is more than 5 round up to the nearest whole number. 11 x 7 = 77 So, 10.8 × 7 = 75.6 is estimate of 77. Multiply. Check for reasonableness. Question 10. 6 × 1.8 = _____________ Answer: Product:10.8 Estimate: 12 Explanation: Estimate: 1.8 If the tenths place is more than 5 round up to the nearest whole number. 6 x 2 = 12 Multiply 6 × 1.8 Count the decimal places. There is one place to the right of the decimal point in 1.8. So, count one place from right to left in the product. So, 6 × 1.8 = 10.8 Check The product 10.8 is close to the estimate 12. So, the answer is reasonable. Question 11. Answer: Product: 23 Estimate: 25 Explanation: Estimate: 4.6 If the tenths place is more than 5 round up to the nearest whole number. 5 x 5 = 25 Multiply 4.6 x 5 Count the decimal places. There is one place to the right of the decimal point in 4.6. So, count one place from right to left in the product. So, 4.6 x 5 = 23.0 Check The product 23.0 is close to the estimate 25. So, the answer is reasonable. Question 12. Answer: Product: 15.036 Estimate: 14 Explanation: Estimate: 7.16 x 2.1 If the tenths place is less than 5 round down to the nearest whole number. 7 x 2 = 14 Multiply 7.16 x 2.1 Count the decimal places. There are 3 places to the right of the decimal point in 7.16 x 2.1. So, count 3 places from right to left in the product. So, 7.16 x 2.1 = 15.036 Check The product 10.8 is close to the estimate 14. So, the answer is reasonable. Multiply. Tell which property you used. Question 13. 50 × (20 × 1.3) = _______________ Answer: 1,300 Explanation: The Associative Property of Multiplication states that the way in which factors are grouped does not change the product. 50 × (20 × 1.3) = (50 x 1.3) x 20 50 x 26 = 65 x 20 1300 = 1300 Question 14. 2 × (50 × 5.6) = _____________ Answer: 560 Explanation: The Associative Property of Multiplication states that the way in which factors are grouped does not change the product. 2 × (50 × 5.6) = 50 x (5.6 x 2) 280 x 2 = 50 x 11.2 560 = 560 Estimate each quotient. Question 15. 20.6 ÷ 4 Answer: 5 Explanation: Round 20.6 to the nearest whole number, 20 and 4 are compatible numbers. Since 5 × 4 = 20 is approximately equal 20.6, the answer is reasonable. Question 16. 24.3 ÷ 8 Answer: 3 Explanation: Round 24.3 to the nearest whole number, 24 and 8 are compatible numbers. Since 3 × 8 = 24 is approximately equal 24.3, the answer is reasonable. Question 17. 118.1 ÷ 10 Answer: 10 Explanation: Round 118.1 to the nearest whole number, 100 and 10 are compatible numbers. Since 10 × 10 = 100 is approximately equal 118.1, the answer is reasonable. Divide. Check your answer using multiplication. Question 18. 102.6 ÷ 102 = ____________ Answer: 1.026 Explanation: Dividing a decimal by 100 moves the decimal point two place to the left. 10= 10 x 10 = 100, the number 100 to explain. 102.6 ÷ 100 = 1.026 as shown below. Check: 1.026 x 100 = 102.6 In multiplication the decimal point moves to 3 points to the right. Question 19. 1.8 ÷ 0.08 = ______________ Answer: 22.5 Explanation: Given, 1.8 ÷ 0.08 by multiplying 10 0.08 x 10 = 0.8 1.8 x 10 = 18 18 ÷ 0.8 = 22.5 Check: Multiply to check your answer. Multiplication and division, are inverse operations of each other. 0.8 x 22.5 = 18 Question 20. Answer: 0.205 Explanation: Given, 6.2 ÷ 12.71 by multiplying 10 6.2 x 10 = 62 12.71 x 10 = 127.1 127.1 ÷ 62 = 0.205 Check: Multiply to check your answer. Multiplication and division, are inverse operations of each other. 0.205 x 62 = 12.71 Problem Solving Question 21. Kasi bought 7 pounds of mozzarella cheese. Each pound costs$4.29. About how much did he spend altogether?
$30.03 or$ 30
Explanation:
Kasi bought 7 pounds of mozzarella cheese.
Each pound costs $4.29. About how much did he spend altogether, 7 x$4.29 = $30.03 Estimate of$30.03 is $30. Question 22. Ariel buys 2 fish tanks at the pet store. Each tank holds 9.7 liters of water. How many liters of water will she need to fill both tanks? Answer: 19.4 liters. Explanation: Ariel buys 2 fish tanks at the pet store. Each tank holds 9.7 liters of water. Total liters of water will she need to fill both tanks, 9.7 x 2 = 19.4 liters. Question 23. It costs$4.25 for one pound of roast beef. How much will it cost to purchase 2.5 pounds of roast beef? Round to the nearest cent.
$11 or$10.625
Explanation:
It costs $4.25 for one pound of roast beef. Cost of 2.5 pounds of roast beef, 2.5 x$4.25 = 10.625

Question 24.
Describe the pattern below. What are the next two numbers?
0.41, 0.82, 1.64, 3.28
6.56, 13.12, 26.24
Explanation:
Each pattern above would be followed by double the number of the previous number.
Given 0.41,
0.41 + 0.41 = 0.82
0.82 + 0.82 = 1.64
1.64 + 1.64 = 3.28
3.28 + 3.28= 6.56
6.56 + 6.56 = 13.12
13.12 + 13.12 = 26.24

Question 25.
The total bill for a dinner party was $113.58. If each person pays$12.62, how many people attended the dinner party?
9 people.
Explanation:
The total bill for a dinner party was $113.58. If each person pays$12.62,
Number of people attended the dinner party,
$113.58 ÷$12.62 = 9

Test Practice

Question 26.
Sofia paints a rectangular mural on the wall. The area of the mural is 128.52 square feet. The mural is 12.6 feet wide. What is the height of the mural?
(A) 115.92 ft
(B) 105.2 ft
(C) 10.2 ft
(D) 8.6 ft
Option(C)
Explanation:
The area of the mural is 128.52 square feet.
The mural is 12.6 feet wide.
Area = Base x Height
128.52 = 12.6 x h
h = 128.52 ÷ 12.6 = 10.2 ft

Reflect

Use what you learned about multiplying and dividing decimals to complete the graphic organizer.

In decimal multiplication, we multiply the numbers without the decimal places,
then we write the total number of decimal places from the sum of both factors for the answer. For division, we move the decimal places on both numbers until the divisor is a whole number, then divide like usual.
Explanation:
Estimate: 25
Explanation:
Multiply 4.6 x 5

Count the decimal places.
There is one place to the right of the decimal point in 4.6.
Divide 6.2 ÷ 12.71
by multiplying 10
6.2 x 10 = 62
12.71 x 10 = 127.1
127.1 ÷ 62 = 0.205

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