# Qual é a soma de  2 / 5  e  2 / 4 ?

9/10

#### Explicação:

First note that 2/4" may be simplified"

cancel(2)^1/cancel(4)^2=1/2

hence 2/5+1/2" is now the sum"

Since the denominators ( 5 and 2 ) are different we cannot add them. We have to have a common denominator before we can do this.
The lowest common denominator for 2 and 5 is 10. We now express both fractions with a denominator of 10.

(2/5xx2/2)+(1/2xx5/5)=4/10+5/10

Now that the denominators are the same we just add the numerators, leaving the denominator(do not add)

rArr2/5+1/2=4/10+5/10=9/10