5 + 7 + 8 = 20
4 + 5 + 6 + 7 + 8 + 9 = 39
9 + 8 + 7 + 6 + 5 + 4 = 39
true. 5+3=8 8+7=15 5+7=12 12+3=15
5*(-8)+7*(9) = 23
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 + 8 + 7 + 6 + 5 + 4 + 3 = 42
it is 28
5/8 + 7/5 = 21/40
8 3/7 + 5 5/7 = 13 8/7 = 14 1/7
24
24
2 + 5 is 7 + 6 =13 + 7 = 20 + 8 = 28 + 9 = 37 + 10 is 47.