assuming it keeps the same pattern of +10 -5 alternating then the next number would be 26
16 21 22 29
a
It is: 34
It is 26 followed by 31
My guess: 2.5
26 As far as I can tell the sequence is +10,-5,+10,-5.
The next number in the sequence 3-15-6-30-21 is -207.
18
The next number in this sequence should be 33.
The next number in this sequence is 13112221.
20
7203