Learn how to use inverse operations to find the value of an unknown variable in an equation, so that the value is true.

But what if you could use your smartphone to solve equations by pointing the camera at the problem in your textbook instead of using a graphing calculator? That is the idea behind PhotoMath.

Share or comment on this article: Simple-looking math equation sees people guess some very topsy-turvy answers - can you solve it in 30 seconds?

Share or comment on this article: Easy looking math equation proves tricky for people - do you know the rule to solve the sum in 30 seconds?

Mathematicians have devised a new way to solve higher-order polynomial equations, ushering in a 'dramatic revision of a basic chapter in algebra'.