Dozens

Do you know a quick way to check if a number is a multiple of two? How about three, four or six?

Book Codes

Look on the back of any modern book and you will find an ISBN code. Take this code and calculate this sum in the way shown. Can you see what the answers always have in common?

The Remainders Game

A game that tests your understanding of remainders.

Neighbours

Stage: 2 Challenge Level:

In a square in which the houses are evenly spaced around the outside, numbers $3$ and $10$ are opposite each other.

What is the smallest number of houses in the square?

What is the largest possible number of houses in the square?