W10.1

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W10.1

Hello I really don't know how to make questions about calculations with decimals interesting, but it is quite important, so let's do it :)

847.8 - 0.34 = ?

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Hint:

use the column method to do this subtraction.

Align your decimal points!!!

You will need to add a zero at the end of 847.8, it won't change the value but will allow you to take away the 0.34.

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a multiplication:

0.2 x 0.4 = ?

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hint:

method 1:

How many numbers do I have after the decimal points? (2)

I do the multiplication without the decimal points. Then I bring the decimal point back in my answer, and put the same number of digits after the decimal point (2).

method 2:

I time my first number by 10 to make it a whole number.

I do the same with the second number.

Finally I need to divide my answer by 10 then 10 again (which is the same as divide by 100)

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and finally a division:

31.2 ÷ 6 = ?

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Hint:

Just do a bus stop method. When you reach the decimal point in the dividend (31.2) put a decimal point in the quotient (the result).

To have a sense of 'scale' for your answer, you can estimate the answer by ignoring the decimal 31 ÷ 6 = ..... and know your answer should be marginaly bigger or smaller.

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Answers:

847.8 – 0.34 = 847.46

0.2 x 0.4 = 0.08

31.2 ÷ 6 = 5.02

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Well done you :)

another question:

What is the best season to practice adding?

answer: sum-mer!