first, we have to get both fractions to a common denominator. both 25 and 20 have the same multiple, 100, so we’ll be using that
convert each fraction to /100. do this by multiplying both sides by whatever the bottom number has to be multiplied by to get 100. for example:
24/25 * 4/4 = 96/100
1/20 * 5/5 = 5/100
then add them together
96/100 + 5/100 = 101/100
so 24/25 + 1/20 = 101/100
this is in simplest form, but it can also be shown as a mixed number, 1 and 1/100