Answer: 1,050 bread crumbs
Step-by-step explanation: First lets add the bread crumbs Jacob and Martha threw in total.
592 + 629 = 1,221 total bread crumbs thrown to the ducks.
If there were 171 bread crumbs left on the floor, and we want to find how many bread crumbs the ducks eat, we can simply subtract 171 from 1,221 bread crumbs.
1,221 - 171 = 1,050 total bread crumbs eaten by the ducks.