Are you asking to add it? 9 tens, and 10 ones:
You have 9 tens, which adds up to 90.
You have ten ones, which adds up to 100.
If you're saying start at 100, it would be 200 because the last answer was 100, and you just add up 100 more.
I hope I did it right, and if I didn't, let me know. I'll find the right way to do it.