23
15
If you mean the fraction 23/15, divide 23 by 15. The whole part will be the whole number; the remainder will be the numerator for the fractional part.
Subtract 8 from 38; divide by 2 for the first number; add 8 for the second number. Example: 38 - 8 = 30 / 2 = 15 (first number). 15 + 8 = 23 (second number). Proof: 15 + 23 = 38.
I think that each number is the previous one plus 8; 7+8=15 15+8=23 23+8=31 31+8=39 39+8=47
8
15-23 = -8
Each number is 8 more than the preceding number.
7
23 - 8 = 15
23-8 = 15
28