Have you manage to solve Cheryl’s birthday yet? You know, without looking at the answer first? Well, don’t worry. There’s a new Maths teaser over from Vietnam that might just allow you to claw back a little a little self-respect - or not as the case may be.

Welcome to the hell of what we’re calling the Arithmetic Snake. Looks harmless enough, doesn’t it? It was set for what can only be assumed is some kind of super-genius group of 8-year-old students in the town of Bao Loc in the Vietnam's highland region.

The idea behind it is simple enough. All you need to do is place the numbers 1 to 9 into the grid in such an order that all of the operations work to offer the magic answer of 66 by the time you reach the end. Give it a go. Oh, and if you haven’t worked the funny colon symbol out, that’s meant to be division.

“This problem is difficult even for adults good at math,” teacher Tran Phuong said to VN Express.

“I sent the problem to some people, including a doctorate in economics with mathematics, but they have not given the answer.”

Trial and error might take you a while but, if you happen to strike it lucky, you might want to give Mr Phuong a call.