**A quick puzzle** to keep things ticking over until the imminent return of the Mad Hatter. Suitable for A-level students and top-end GCSE, or even KS3. Has been known to stump maths teachers too:

**#7: Gridlock
**

*A deceptively simple puzzle. Fill in the grid.*

**Published:**29/07/2015

**Difficulty: ***

**Maths knowledge required:**Very basic – calculating means.

The solution will be available next week.

**IMAGE: ***IDS.photos – Creative Commons*

*The giant crab that I have chosen to illustrate this post is not relevant to the puzzle, but bonus points go to anyone who knows why I have picked it and can provide an appropriate response…*

**DIFFICULTY RATINGS:
**

*****– Not too taxing

******– Requires significant thought

*******– Extremely difficult

**!!!!**– Requires high level mathematics / Unsolved / Insoluble