when dividing 918 by 4.2, what number should the divisor be multiplied by in order to make it a whole number

To make 4.2 a whole number, we need to make the decimal places equal to zeros

4.2 = 4 + 0.2

Think of a number that multiplied by 0.2 gives a whole number. The smallest number possible will be 5 since 0.2 × 5 = 1

So we multiply 4.2 by 5

4.2 × 5 = [4 × 5] + [0.2 × 5] = 20 + 1 = 21

Applying this change into the whole sum

918 ÷ 4.2 
[918 ÷ 4.2] × 5 = [918 × 5] ÷ [4.2 × 5] = 4590 ÷ 21 

Now you have a sum whose terms in whole numbers only

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