[Math] Next number in series

algebra-precalculuspuzzlesequences-and-series

What are the basic/advanced strategies used to find the next number in series.

I know the simple ones such as addition, multiplication etc. But recently I came into a question that goes on something like 812, 819, 823, 835, 834, 851(Don't try to solve this, I changed some numbers and there is no sequence). This is to illustrate that the sequence goes up and goes down at 835 then goes back up. What strategies can you use to solve it?

These questions are for an aptitude test so you have about 60-90 secs to solve each question.

P.S. I can't really post the question that was asked as I might be disqualified from the job process if I post it.

Best Answer

The answer is 42. Always.