-13
It is 15-4 = 11
the next number is 5 and the one after that is 15
What would be the next number in this series 15 12 13 10 11 8?
The next number in the series 7, 9, 11, 13, 15 is 17. This series is an arithmetic progression where each number increases by 2. Thus, adding 2 to the last number, 15, gives us 17.
the answer is 1
14
17
11 15 16
it is the number such that 15 added to negative 15=0
4 + (-15) = 4 - 15 = -11
8
10 4 3 11 15 9 8 16 20....