You may also like

Prompt Cards

These two group activities use mathematical reasoning - one is numerical, one geometric.

Consecutive Numbers

An investigation involving adding and subtracting sets of consecutive numbers. Lots to find out, lots to explore.

Exploring Wild & Wonderful Number Patterns

EWWNP means Exploring Wild and Wonderful Number Patterns Created by Yourself! Investigate what happens if we create number patterns using some simple rules.

X Is 5 Squares

Age 7 to 11
Challenge Level

Can you arrange five different digits (from 0 to 9) in the cross so that

  1. the total of the four outside numbers is equal to the middle number, and
  2. the top two numbers multiplied together are also equal to the middle number, and
  3. the sum of the three numbers forming a diagonal is equal to the other three numbers forming the other diagonal.

Diagonal cross consisting of 5 squares.


The NRICH Project aims to enrich the mathematical experiences of all learners. To support this aim, members of the NRICH team work in a wide range of capacities, including providing professional development for teachers wishing to embed rich mathematical tasks into everyday classroom practice.
Copyright © 1997 - 2022. University of Cambridge. All rights reserved.
NRICH is part of the family of activities in the Millennium Mathematics Project.