A case contains c cartons. Each carton contains b boxes, and each box contains 100 paper clips. find out how many paper clips are there in 2 cases.
Magnet A can hold three paper clips, magnet B can hold four paper clips, and magnet C can hold five paper clips. The strongest and the weakest magnets are __________.
How many marbles are there in 5n boxes, each containing 3m marbles?