Question

-9,101,-999,10001,-99999........
Find the next three terms in each sequense

Answer 1

The sequence seems to alternate between two kind of states: either -9...9 or 10...01. We're just looking for patterns here. The last one is -99999, that's five 9's. So the next one should be 10...01, but how many 0's? In each previous term, the number of 0's is the same as the number of 9's in the term right before it. So five 9's means the next term has five 0's, so next is 1000001.

After that, we switch back to -9...9. Can you find a pattern that tells us how many 9's we should have, based on the previous number?

Another way to do this problem would be coming up with a formula. We can try that if you're still stuck.

Answer 2

what formular we use in this case?

Answer 3

I think we time 2 "00" and 2"99" for each time.

Answer 4

Right! Figure out which of the two kinds of terms we're at, and just have two more 0's or 9's than before. That should work.

Answer 5

0k thanks