You are given a math word problem and you are supposed to apply a single mathematical operator like addition, subtraction, multiplication, or division on the numbers embedded in the text to answer the following question and then only report the final numerical answer.

18 children were riding on the bus . at the bus stop some more children got on the bus . then there were 25 children altogether on the bus . how many children got on the bus at the bus stop ?
7

there were 3409 pieces of candy in a jar . if 145 pieces were red and the rest were blue how many were blue ?
3264

2 beavers were working on their home . 1 went for a swim . how many beavers are still working on their home ?
1