You cannot add two fractions with different denominators (the bottom number) so you have to convert them so that they do.
The lowest common denominator (LCD) for 4 and 5 is 20. 4 is multiplied into 20 5 times, so multiply 5/5 by the whole fraction so that you have:
1/4x5/5=5/20
And as for 5, it goes into 20 4 times, so you multiply 4/4 by the whole fraction so that you have:
3/5x4/4=12/20
NOW, you can add both fractions together. Because this is addition, you do NOT add the denominators, only add the numerators.
5/20+12/20=17/20
The fraction 17/20 cannot be simplified any further, so that is your answer. Hope this helps :-)
