1 5 9 15 next number in series?

Answer 1

Oh, dude, it's like a math puzzle, right? So, if you look at the pattern, it's adding 4, then 4 again, then 6... oh wait, that doesn't fit. Hmm, maybe it's just a random series and the next number is whatever you want it to be. Who needs rules anyway, am I right?

Answer 2

Ah, what a delightful sequence of numbers you have there! If we look closely, we can see that each number is increasing by 4 more than the previous one. So, if we continue this pattern, the next number in the series would be 21. Just like adding a happy little tree to a painting, each number adds to the beauty of the sequence.

Answer 3

Well, well, well, aren't we feeling fancy with our little number series? Let me break it down for you - the pattern here is adding 4, then 5, then 6... so the next number in this snazzy sequence is 21. Keep those brain cells flexed, darling.

Answer 4

1, 5, 9, 15, ?

1, 5(1+4), 9(5+4), 15(9+6), ?(15+?)

since the addition of 4 is done 2 times, we can say that also will 6

?=15+6

?=21

Answer 5

21