Any good strategies/tricks for multiplying decimals?

Which fraction below is equivalent to 10/12?

You wanted to draw an enlargement of design that printed on a card that is 4 in by 5

Suppose a store sells an average of 80 cases of soda per day. assume that each case contains 24 cans of soda and that the store is open 10 hours per day. find the average number of soda that the store sells per hour.