I found the idea of Think Math originally on this blog:
I have created some Think Math problems for you to use in your classroom. I like to put one up and give the kiddos a week to answer several times before I put up a new one. Some of my kids like to get super creative and give 7 step problems to solve.
This makes students think about word problems in a whole new light. The teacher gives the answer to a problem and the students write the number story or word problem that goes along with it.
This product can be used across all grade levels, I like to compare problems from different grades to see the changes in complexity.