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Number Round Up

Arrange the numbers 1 to 6 in each set of circles below. The sum of each side of the triangle should equal the number in its centre.

Number Detective

Follow the clues to find the mystery number.

Grouping Goodies

Pat counts her sweets in different groups and both times she has some left over. How many sweets could she have had?

Carroll Diagrams

Age 5 to 11
Challenge Level


What do you know about the number 1? Where would it go?
How about the number 1? And 3?
You could look at all the odd numbers first, for example, and decide where they go in the diagram.

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.
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NRICH is part of the family of activities in the Millennium Mathematics Project.