Donovan is going to add many numbers. each number will use only the digit 1. what is the greatest number of addends donovan can use without having to regroup?

1+1+1+1+1+1+1+1+1=9 . Adding 1 together 9 times gives you the highest possible sum without having to regroup.

Adding 1 together 10 times gives you a product of 10 which would make you have to regroup.

goodluck and count your change the next time you go buy something