What is a trick for multiplying by the 12s?

Answer 1

First, multiply the original number by 10. Then multiply the original number by 2. Add the two answers that you got and you have just multiplied by 12.

For Example: 7x12=(7x10)+(7x2)

70+14

84

Answer 2

One trick for multiplying by 12 is to multiply the number by 10 and then add two times the number. For example, if you want to multiply 7 by 12, first multiply 7 by 10 to get 70, and then add 7*2=14 to get 84.