Each mental maths challenge is 5 minutes long. They are usually carried out once a week in school, although you're welcome to practise at home, too. To gain a certificate, you need to answer all the questions correctly within the time limit. (If you're on Level 10 or above, you're allowed one mistake!)

The challenges have been designed to be:

• inclusive: Nearly anybody (child or adult!) will be able to find just the right level of challenge.
• progressive: Moving up a level will never mean that any types of question disappear. Instead, the numbers involved may get bigger, and more complex types of calculations may be introduced. Each level also has five more questions than the previous.
• useful: The questions presented will not always have a gap after the equals sign; it may be anywhere in the question, and the equals sign may be on either side (e.g. 10 = ? + 4), encouraging deeper understanding.
• randomised: Every individual challenge generates a new set of random questions, within the constraints of its level, so learners must understand what they are doing and not just learn answers by rote.
• accessible: Pupils can practise at home, either using a timed, self-marking, online version or the same paper-based version they will see in school.

Teachers can produce class sets on this page. You can specify how many of each level you'd like and whether you'd like answer sheets for all, some or none. Because the mental maths challenges are randomised, you are advised to produce a new class set each week, instead of photocopying.

You can also download a mark book, which will highlight when pupils complete levels, and show you how many of each level you need each week (at the bottom of the page). Hover over the cells with red triangles in their corners for pop-up help.

Finally, you can craft your own challenges on this page by specifying how many of each type of question, and what ranges of numbers should be used.

If you're using the mental maths challenges at a different school (or in another educational setting), please let us know. It won't make any tangible difference but will give us a nice feeling of contentment in our tummies. We might like to list the schools that are using these challenges, too, but won't do so without your permission.