9/15 + 9/11
This is addition of fractions.
Steps to take :-
#1; Convert to improper fractions. (NB not required in this case)
#2; Bring to a Common Denominator, by multiplying together the denominators.
#3; Convert the numerators to equivalent values.
#4; Add the numerators.
#5; Place over the denominator.
#6; Convert to a mixed fraction/number.
#1 Not required
#2 ; 15 x 11 = 165
#3 ; 9 x 11 = 99 & 9 x 15 = 135
#4 ; 99 + 135 = 234
#5 ; 234/ 165
#6 ; ( 1 69/165 ) ; reduce the fraction by cancelling down by '3' . Hence 1 69/165 = 1 23/55 is the answer.
NB ; For subtraction of fractions, follow that same steps, except at #4 subtract the numerators.