Practice the problems of Math in Focus Grade 5 Workbook Answer Key Chapter 9 Practice 1 Multiplying Decimals to score better marks in the exam.
Math in Focus Grade 5 Chapter 9 Practice 1 Answer Key Multiplying Decimals
Multiply. Write the product as a decimal.
Example
2 × 0.3 = 2 × 3 tenths
= 6 tenths
0.6
So, 2 × 0.3 = 0.6
Question 1.
5 × 0.6 = 5 × ____ tenths
= ___ tenths
= ____ or ____
So, 5 × 0.6 = ____
Answer:
5 × 0.6 = 5 × 6 tenths
= 30 tenths
= 3.0 or 3
So, 5 × 0.6 = 3
Explanation:
To multiply a decimal number by a decimal number,
we first multiply the two numbers ignoring the decimal points and then;
place the decimal point in the product in such a way that;
decimal places in the product is equal to the sum of the decimal places in the given numbers.
Question 2.
7 × 0.8 = 7 × ___ tenths
= ___ tenths
= _____
So, 7 × 0.8 = ___
Answer:
7 × 0.8 = 7 × 8 tenths
= 56 tenths
= 5.6
So, 7 × 0.8 = 5.6
Explanation:
To multiply a decimal number by a decimal number,
we first multiply the two numbers ignoring the decimal points and then;
place the decimal point in the product in such a way that;
decimal places in the product is equal to the sum of the decimal places in the given numbers.
Question 3.
10 × 0.4 = 10 × ___ tenths
= ___ tenths or
= ___ or ___
So, 10 × 0.4 = ___
Answer:
10 × 0.4 = 10 × 4 tenths
= 4 tenths or
= 4.0 or 4
So, 10 × 0.4 = 4
Explanation:
To multiply a decimal number by a decimal number,
we first multiply the two numbers ignoring the decimal points and then;
place the decimal point in the product in such a way that;
decimal places in the product is equal to the sum of the decimal places in the given numbers.
Multiply. Write the product as a decimal.
Example
3 × 0.03 = 3 × 3
= 9 hundredths
= 0.09
So, 3 × 0.03 = 0.09
Question 4.
5 × 0.02 = 5 × ___ hundredths
= ____ hundredths
= ___ or _____
So, 5 × 0.02 = ____
Answer:
5 × 0.02 = 5 × 2 hundredths
= 10 hundredths
= 10/100 or 0.1
So, 5 × 0.02 = 0.1
Explanation:
To multiply decimals, first multiply as if there is no decimal.
Next, count the number of digits after the decimal in each factor.
Finally, when only one factor has decimal place value,
the product will have as many decimal place values as that one factor.
Question 5.
7 × 0.07 = 7 × ___ hundredths
= ____ hundredths
= ___ or _____
So, 7 × 0.07 = ____
Answer:
7 × 0.07 = 7 × 7 hundredths
= 49 hundredths
= 49/100 or 0.49
So, 7 × 0.07 = 0.49
Explanation:
To multiply decimals, first multiply as if there is no decimal.
Next, count the number of digits after the decimal in each factor.
Finally, when only one factor has decimal place value,
the product will have as many decimal place values as that one factor.
Question 6.
6 × 0.12 = 6 × ___ hundredths
= ____ hundredths
= ___
So, 6 × 0.12 = ____
Answer:
6 × 0.12 = 6 × 12 hundredths
= 72 hundredths
= 0.72
So, 6 × 0.12 = 0.72
Explanation:
To multiply decimals, first multiply as if there is no decimal.
Next, count the number of digits after the decimal in each factor.
Finally, when only one factor has decimal place value,
the product will have as many decimal place values as that one factor.
Follow the steps to multiply 2.6 by 3. Fill in the blanks.
Question 7.
Multiply the tenths by 3.
3 × 6 tenths = _18_ tenths
Regroup the tenths.
18___ tenths = _1__ one and __6_ tenths
Step 2
Multiply the tenths by 3.
3 × 2 ones = _6__ ones
Add the ones.
_6__ ones + _1_ one = _7_ ones
So, 3 × 2.6 = _7.8__
Multiply.
Question 8.
Answer: 2.4
Explanation:
Multiply the tenths by 8.
8 × 3 tenths = 24 tenths
Regroup the tenths.
24 tenths = 2 one and 4 tenths
Step 2
Multiply the tenths by 8.
8 × 0 ones = 0 ones
Add the ones.
0 ones + 2 one = 2 ones
So, 0.3 × 8 = 2.4
Question 9.
Answer: 10.4
Explanation:
Multiply the tenths by 4.
4 × 6 tenths = 24 tenths
Regroup the tenths.
24 tenths = 2 one and 4 tenths
Step 2
Multiply the tenths by 4.
4 × 2 ones = 8 ones
Add the ones.
8 ones + 2 one = 10 ones
So, 2.6 × 4 = 10.4
Question 10.
Answer: 39.5
Explanation:
Multiply the tenths by 5.
5 × 9 tenths = 45 tenths
Regroup the tenths.
45 tenths = 4 one and 5 tenths
Step 2
Multiply the tenths by 5.
5 × 7 ones = 35 ones
Add the ones.
35 ones + 4 one = 39 ones
So, 7.9 × 5 = 39.5
Question 11.
Answer: 86.8
Explanation:
Multiply the tenths by 7.
7 × 4 tenths = 28 tenths
Regroup the tenths.
28 tenths = 2 one and 8 tenths
Step 2
Multiply the tenths by 5.
7 × 12 ones = 84 ones
Add the ones.
84 ones + 2 one = 86 ones
So, 12.4 × 7 = 86.8
Question 12.
Step 1
Answer: 8.76
Explanation:
Multiply the hundredths by 6.
6 × 6 hundredths =36 hundredths
Regroup the tenths.
36 hundredths = 3 tenths and 6 hundredths
Step 2
Multiply the tenths by 6.
6 × 4 tenths = 24 tenths
Add the tenths.
24 tenths + 3 tenths = 27 tenths
Regroup the tenths.
27 tenths = 2 ones and 7 tenths
Step 3
Multiply the ones by 6.
6 × 1 ones = 6 ones
Add the ones.
6 ones + 2 ones = 8 ones
So, 6 × 1.46 = 8.76
Multiply.
Question 13.
Answer: 50.07
Explanation:
Multiply the hundredths by 5.
5 × 7 hundredths =35 hundredths
Regroup the tenths.
35 hundredths = 3 tenths and 5 hundredths
Step 2
Multiply the tenths by 5.
5 × 0 tenths = 0 tenths
Add the tenths.
0 tenths + 3 tenths = 3 tenths
Regroup the tenths.
3 tenths = 0 ones and 3 tenths
Step 3
Multiply the ones by 6.
5 × 10 ones = 50 ones
Add the ones.
50 ones + 0 ones = 50 ones
So, 5 × 10.07 = 50.35
Question 14.
Answer: 3
Explanation:
Multiply the tenths by 4.
4 × 5 tenths = 20 tenths
Regroup the tenths.
20 tenths = 2 one and 0 tenths
Step 2
Multiply the tenths by 4.
4 × 7 ones = 28 ones
Add the ones.
28 ones + 2 one = 2 ones
So, 0.75 × 4 = 3
Question 15.
Answer: 27.54
Explanation:
Multiply the hundredths by 9.
9 × 6 hundredths =54 hundredths
Regroup the tenths.
54 hundredths = 5 tenths and 4 hundredths
Step 2
Multiply the tenths by 9.
9 × 0 tenths = 0 tenths
Add the tenths.
0 tenths + 54 tenths = 54 tenths
Regroup the tenths.
54 tenths = 5 ones and 4 tenths
Step 3
Multiply the ones by 9.
9 × 3 ones = 27 ones
Add the ones.
27 ones + 0 ones = 27 ones
So, 9 × 3.06 = 27.54
Question 16.
Answer: 121.92
Explanation:
Multiply the hundredths by 8.
8 × 4 hundredths =32 hundredths
Regroup the tenths.
32 hundredths = 3 tenths and 2 hundredths
Step 2
Multiply the tenths by 8.
8 × 2 tenths = 16 tenths
Add the tenths.
16 tenths + 3 tenths = 3 tenths
Regroup the tenths = 19
Step 3
Multiply the ones by 8.
8 × 15 ones = 120 ones
Add the ones.
120 ones + 1 ones = 121 ones
So, 8 × 15.24 = 121.92
Question 17.
4 × 2.08 = ___
Answer: 8.32
Explanation:
Multiply the hundredths by 4.
4 × 8 hundredths =32 hundredths
Regroup the tenths.
32 hundredths = 3 tenths and 2 hundredths
Step 2
Multiply the tenths by 4.
4 × 0 tenths = 16 tenths
Add the tenths.
0 tenths + 3 tenths = 3 tenths
Step 3
Multiply the ones by 4.
4 × 2 ones = 8 ones
Add the ones.
8 ones + 32 ones = 8.32 ones
So, 4 × 2.o8 = 8.32
Question 18.
3 × 3.29 = ___
Answer: 9.87
Explanation:
Multiply the hundredths by 3.
9 × 3 hundredths =27 hundredths
Regroup the tenths.
27 hundredths = 2 tenths and 7 hundredths
Step 2
Multiply the tenths by 3.
3 × 2 tenths = 6 tenths
Add the tenths.
6 tenths + 0 tenths = 6 tenths
Regroup the tenths
6 tenths + 2 tenths = 8 tenths
Step 3
Multiply the ones by 6.
6 × 3 ones = 18 ones
Add the ones.
8 ones + 1 ones = 9 ones
So, 3 × 3.29 = 9.87
Question 19.
7 × 5.71 = ___
Answer: 39.97
Explanation:
Multiply the hundredths by 7.
1 × 7 hundredths =7 hundredths
Regroup the tenths.
7 hundredths = 0 tenths and 7 hundredths
Step 2
Multiply the tenths by 7.
7 × 7 tenths = 49 tenths
Add the tenths.
49 tenths + 0 tenths = 49 tenths
Regroup the tenths
49 tenths = 4 ones and 7 tenths
Step 3
Multiply the ones by 7.
5 × 7 ones = 35 ones
Add the ones.
35 ones + 4 ones = 39 ones
So, 7 × 5.71 = 39.97
Question 20.
6 × 4.81 = ___
Answer: 28.86
Explanation:
Multiply the hundredths by 6.
1 × 6 hundredths =6 hundredths
Regroup the tenths.
6 hundredths = 0 tenths and 6 hundredths
Step 2
Multiply the tenths by 6.
8 × 7 tenths = 48 tenths
Add the tenths.
48 tenths + 0 tenths = 48 tenths
Regroup the tenths
48 tenths = 4 ones and 8 tenths
Step 3
Multiply the ones by 6.
4 × 6 ones = 24 ones
Add the ones.
24 ones + 4 ones = 28 ones
So, 6 × 4.81 = 28.81
Question 21.
9 × 7.46 = ___
Answer: 67.14
Explanation:
Multiply the hundredths by 9.
9 × 6 hundredths =54 hundredths
Regroup the tenths.
54 hundredths = 5 tenths and 4 hundredths
Step 2
Multiply the tenths by 9.
9 × 4 tenths = 36 tenths
Add the tenths.
36 tenths + 5 tenths = 41 tenths
Regroup the tenths
41 tenths = 4 ones and 1 tenths
Step 3
Multiply the ones by 9.
9 × 7 ones = 63 ones
Add the ones.
63 ones + 4 ones = 67 ones
So, 9 × 7.46 = 67.14
Question 22.
8 × 6.52 = ___
Answer: 52.16
Explanation:
Multiply the hundredths by 8.
8 × 2 hundredths =16 hundredths
Regroup the tenths.
16 hundredths = 1 tenths and 6 hundredths
Step 2
Multiply the tenths by 8.
8 × 5 tenths = 40 tenths
Add the tenths.
40 tenths + 1 tenths = 41 tenths
Regroup the tenths
41 tenths = 4 ones and 1 tenths
Step 3
Multiply the ones by 8.
8 × 6 ones = 48 ones
Add the ones.
48 ones + 4 ones = 52 ones
8 × 6.52 = 52.16
Write the correct decimal in each box.
Example
Question 23.
Answer: 21.38
Explanation:
0.46 x 3
3 × 0.46 = 3 × 46 hundredths
= 138 hundredths
= 1.38
So, 3 × 0.46 = 1.38
20+1.38 = 21.38
Question 24.
Answer:20.04
Explanation:
6 x 0.84
6 × 0.84 = 6 × 84 hundredths
= 504 hundredths
= 5.04
So, 6 × 0.84 = 5.04
15+5.04 = 20.04
Question 25.
Answer: 31.4
Explanation:
5×1.28
5 × 1.28 = 5 ×128 hundredths
= 640 hundredths
= 6.40
So, 5 × 1.28 = 6.40
25+6.40 = 31.4