Multiplications of decimals
When multiplying a decimal by multiples of 10(100,1000,10000....) we move the decimal point to the right depending on the number of zero(s).
Example
Multiply the following:
- 1.34 × 10
- 14.657 × 100
- 6.05 × 1000
Solutions
a. 1.34 × 10
move the decimal point once to the right since there is only one zero.
b. 14.657 × 100
Move the decimal point twice to the right since there are two zeros.
C. 6.05 × 1000
Move the decimal point three times to the right since there are three zeros
Example 2
Simplify the following:
- 6.452 × 500
- 3.6 × 20
- 12.42 × 800
Solutions
a. 6.452 × 500
Step 1:split 500 into: 100 × 5
Step 2: multiply 6.452 by 100
6.452 × 100 = 645.2
Step 3: multiply the result by 5.
645.2 × 5 = 3226
b. 3.6 × 20
Step 1: split 20 into: 10 × 2
Step 2: multiply 3.6 by 10
3.6 × 10 = 36
Step 3: multiply result by 2.
36 × 2 = 72.
c. 12.42 × 800
*follow the same steps as in (a.) and (b.)
100 × 8
12.42 × 100 = 1242.0
12.42 × 8 = 9936.
Sample 3
Simplify the following
a. 2.32 × 15
b. 14.42 × 2.5
c. 32.45 × 62
Solutions
2.32 × 15
Step 1: Remove the decimal point and multiply as whole numbers.
Step 2: Put back the decimal point to indicate decimal place. Put the decimal point according to the number if decimal places in the question
The total number of decimal places in the question is two.
Therefore the answer should be in two decimal places.
3480 = 34.80.
(b.) 14.42 × 2.5
Step 1: remove the decimal point and multiply as whole numbers
Step 2: put back the decimal point according to the number of decimal places in the question.
Divisions of decimals
When dividing decimal numbers by multiples of 10, we move the decimal point to the left according to the number of zero(s).
Sample 1
Divide the following:
(a). 4.75 ÷ 10
(b). 8.62 ÷ 100
(c) 1.85 ÷ 1000
Solution
4.75 ÷ 10
*Move the decimal point once to the left since there is only one zero and replace zero at the start if there is no number left.
(b). 8.62 ÷ 100
8.62 ÷ 100 = 0.0862
(c).1.85 ÷ 1000 = 0.00185
Sample 2
Divide the following
(a).55.34 by 300
(b). 7.23 by 400
Solution
55.34 ÷ 300
Step 1: split 300 into: 100 × 3
Step 2: divide 55.34 by splitted 300.
(b). 7.23 ÷ 400
Step 1: Split 400 into: 100 × 4
Step 2: Divide 7.23 by splited 400.
Sample 3
Divide the following:
(a). 3.4 by 0.17
(b). 14.8 by 2.6
Solutions:
Step 1: change decimals to fractions. We learnt how to do so in our last class.
Step 2: Simplify the fractions. We have also learnt how to do this
(b). Follow the same method as in (a).
Assignment
1). Multiply the following
- 64.2 × 100
- 49.07 × 500
- 67.26 × 10
6.987 × 7.24
2). Divide the following
- 48.65 ÷ 100
- 6.24 ÷ 1000
- 2.4 ÷ 0.6
- 6.7 ÷ 400
Rules
Heading should be Assigned homework task for steemkids: Multiplication and division decimals.
Use hashtags #steemkidslessons #yourcountry #steemexclusive among you tags.
please mention @madilyn02 and @steemkidss anywhere in your post.
Remember to drop your link in the comment session of this post.
Entry will last for 7 days from date of this post.
Reward
@steemkidss will share 5 steem among all participants in the assignment.
Cc:
@ngoenyi
@steemkidss