Here are the step-by-step solutions for the questions on the worksheet.
1. 0.3 x 0.5
* First, ignore the decimal points and multiply the numbers like whole numbers: $3 \times 5 = 15$.
* Next, count the total decimal places in the original problem.
* $0.3$ has
1 decimal place.
* $0.5$ has
1 decimal place.
* Total decimal places needed: $1 + 1 = 2$.
* Place the decimal point in your answer (15) so there are 2 digits behind it. You need to add a zero at the front to make room:
0.15.
2. How many digits will be behind the decimal in the product? 0.15 x 0.6
* Count the decimal places in each number:
* $0.15$ has
2 decimal places.
* $0.6$ has
1 decimal place.
* Add them together: $2 + 1 = 3$.
* There will be
3 digits behind the decimal point.
3. 0.2 x 0.8
* Multiply the whole numbers: $2 \times 8 = 16$.
* Count the decimal places:
* $0.2$ has
1 decimal place.
* $0.8$ has
1 decimal place.
* Total: $1 + 1 = 2$.
* Move the decimal point 2 places to the left in the number 16:
0.16.
4. How many digits will be behind the decimal in the product? 1.5 x 0.6
* Count the decimal places:
* $1.5$ has
1 decimal place.
* $0.6$ has
1 decimal place.
* Add them together: $1 + 1 = 2$.
* There will be
2 digits behind the decimal point. (Note: Even though $1.5 \times 0.6 = 0.90$, which simplifies to $0.9$, the initial placement requires 2 spots).
5. What is the correct location of the decimal point in the product? 22.2 x 0.44 = 9768
* Count the decimal places in the factors:
* $22.2$ has
1 decimal place.
* $0.44$ has
2 decimal places.
* Total: $1 + 2 = 3$.
* The answer must have 3 digits after the decimal point.
* Starting from the right of 9768, count 3 spaces to the left: 9.
768.
6. What is the correct location of the decimal point in the product? 2.39 x 4.37 = 104443
* Count the decimal places in the factors:
* $2.39$ has
2 decimal places.
* $4.37$ has
2 decimal places.
* Total: $2 + 2 = 4$.
* The answer must have 4 digits after the decimal point.
* Starting from the right of 104443, count 4 spaces to the left: 10.
4443.
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Final Answer:
1. A
2. C
3. D
4. C
5. D
6. B
Parent Tip: Review the logic above to help your child master the concept of math 8 worksheet.
