you go to the grocery store and see that candy bars are $1.50 each. you want five. so multiply 1.5 times five. you want to know how many oreos are in a full package. you count the rows and columns...
Every time you hand over money to pay for something. You expect the change, so if you hand over a £10 note and bought something for £6 then you subtract 6 from 10 and expect to get £4 in change.