The similar shortcut for division works because division is the opposite operation of multiplication—it “undoes” multiplication. If we move the decimal point to the right when multiplying by 10, 100, 1000 and so on, then it is quite natural that the rule for division would work the “opposite” way.
Probably the last two, cause there's so many white marbles and there's three red ones so like, you could probably pull a red so that your chance of getting blue in the last answer is higher
