Positive 25 that's the answer
The most accurate "estimation" for 5+4 is um... 9
The way you wrote them was right
1/2 - 2/15= 15-4/30 = 11/30 this means that if you were to add 11/30 to 2/15 is exactly equal to 1/2, to fully answer your question you can use any value above that like 12/30 (keep in mind you have to simplify) = 6/15 = 2/5. But then again your question says to add any number to make it greater than 1/2 so technically you could just add 100 or 200 or 1/2 to make the sum of it greater than one half
