21
3+6+5+7+(9-7)=23
1+3+5+7+9=25
6+9+7-5=17 that is the answer
4 + 5 + 6 + 7 + 8 + 9 = 39
9 + 8 + 7 + 6 + 5 + 4 = 39
Do you mean 9 plus 5 minus 7 minus 5? If so, the equation would be: 9+5-7-5=2
5/7 + 9 = 5/7 + 63/7 = 68/7
5*(-8)+7*(9) = 23
9 + 6 + 9 + 6 + 9 + 8 + 5 + 2 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1 = 99
9 + 8 + 7 + 6 + 5 + 4 + 3 = 42
If you put the numbers in order it is: 0, 0, 1, 2, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 7, 7, 7, 7, 8, 9. Since there are 25 numbers, we are looking for the thirteenth number, which is 5.
9+7+5+3+1 16+5+3+1 21+3+1 24+1 25