Each time students visit the NRICH site there will be some activities which are 'live'. That means we are inviting students to send us their solutions and we will publish a selection of them, along with their name and school's name. If you'd like to know more about what we're looking for, read this short article.

The last day for sending in solutions to these live problems is Monday 27 November.

problem

Favourite

### Take Three From Five

Caroline and James pick sets of five numbers. Charlie tries to find three that add together to make a multiple of three. Can they stop him?

problem

Favourite

### Cuboid challenge

What's the largest volume of box you can make from a square of paper?

problem

Favourite

### Slick Summing

Watch the video to see how Charlie works out the sum. Can you adapt his method?