1/9+1/5. Lowest common denominator (a number they both divide into exactly). They both divide into 5 times 9=45. 1/9=5/45 and 1/5=9/45.
So the sum becomes 5/45+9/45, or 5 45ths plus 9 45ths. 5 of anything plus 9 of the same thing = 14 of the thing. So we have 14/45 as the answer.