10
You need to add 6 - (-9) = 6 + 9 = 15.
you need to add +9 +9-7 = +2
you have thirteen, this is because you do... 9+4 because you took away 4, so you need to add it back on. and as you add 1 and then take 1 away that equals zero. so all you need to do is 9+4=13
add 9 add 1 subtract 20 add 9 add 1
-8
It is: -9+16 = 7
10 - (-9) = 19
-9 + 11 = 2
- 8 + 17 = 9 =========
9 - (-6) = 9 + 6 = 15
Well, darling, the common denominator for 1/3 and 4/9 is 9. You see, to add or subtract fractions, you need a common denominator, and in this case, multiplying 3 by 3 gives you 9. So, there you have it, simple math for a simple question.
19