tom sold half of his comic books and then bought 6 more .he now has 12.how many did he begin with?

Question

im trying to figure out how many did he begin with

Answer 1

This is a problem where you need to work backwards. Here's what Tom did originally:

1) Had some comic books

2) sold half

3) bought 6

4) has 12

 

Lets start from the end and go backwards:

4) Tom has 12 comic books

3) He just bought 6. How many did he have before this? You want to undo what he just bought (added) so subtract 6.

2) He'd sold half his collection, so he has half left. Double the amount you got from the previous step to figure out what it is half of.

1) This is how many he started with!