Question

How do you simplify the fraction `15/36`?

Answer 1

Showing a little trick
`5/12`

Explanation:

`color(blue)("The trick")`

Consider the numbers given:

Adding the digits of the 15 of `15/36`

`1+5=6` and 6 is exactly divisible by 3 thus so is 15

Adding the digits of the 36 of `15/36`

`3+6=9` and 9 is exactly divisible by 3 thus so is 36
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`color(blue)("Answering the question")`

`15/36-=(15-:3)/(36-:3) = 5/12`

The `-=` means 'equivalent to'

5 is a prime number so we can not simplify any further.