Question

Phil ate `2/5` of a pizza, Caroline ate `1/4` of a pizza. How much did they eat in all?

Answer 1

`13/20` of a pizza

Explanation:

Convert each fraction so that it has a common denominator. 5 and 4 are common factors of 20, so let's use 20 in the denominator.

`2/5=2/5*1=2/5*4/4=8/20`

`1/4=1/4*1=1/4*5/5=5/20`

Now it's easy to add them:

`8/20+5/20=13/20`

Answer 2

Phil and Caroline ate `13/20` of the pizza in all.

Explanation:

The lowest common multiple of `5` and `4` is 20.

`20/5 = 4`
Multiplying the numerator and denominator of `2/5` by `4`:
`(2*4)/(5*4) = 8/20`

`20/4 = 5`
Multiplying the numerator and denominator of `1/4` by `5`:
`(1*5)/(4*5) = 5/20`

Now that both fractions have the same denominator, we can add their numerators and keep the same denominator.
`2/5 + 1/4 = 8/20 + 5/20 = 13/20`