Question

How do you write $ 8.7\% $ as a decimal?

Answer 1

Hint: A percentage is a number or ratio expressed as a fraction of 100 (from Latin per centum "by a hundred"). So, to remove the percentage symbol we have to divide it by $ 100 $ . And it can be represented as a number by appropriately dividing the numbers and expressing the answer using decimal representation.

Complete step-by-step answer:
Percentage means parts per hundred. For example, $ 50\% $ means a half. So, when we remove the $ \% $ sign we have to introduce $ 100 $ in the denominator, which means that $ 8.7\% = \dfrac{{8.7}}{{100}} $
Now, dividing a number by a multiple of $ 10 $ is easy as we just have to count the number of zeros in the divisor (denominator) and move the decimal point towards the left side by that much number of places.
So, here $ \dfrac{{8.7}}{{100}} = 0.087 $ .
Observe that we have moved the decimal places two positions in the left side as the $ 8.7 $ is divided by $ 100 $ and it has two zeros.
So, $ 8.7\% $ can be written as $ 0.087 $ in the decimal form.
So, the correct answer is “ $ 0.087 $ ”.

Note: Remember that we have to be careful while moving the decimal point. Carefully count the number of zeros in the denominator and move the decimal point to the left by that much number of places.
Also, note that we can add, subtract, divide and multiply two percentages in the usual way. But when you want to add, subtract, multiply or divide a percentage with a number, then you will have to convert it to a fraction or decimal first then perform the operation with the number.