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Days and Dates

Investigate how you can work out what day of the week your birthday will be on next year, and the year after...

Natural Sum

The picture illustrates the sum 1 + 2 + 3 + 4 = (4 x 5)/2. Prove the general formula for the sum of the first n natural numbers and the formula for the sum of the cubes of the first n natural numbers.

Series Sums

Let S1 = 1 , S2 = 2 + 3, S3 = 4 + 5 + 6 ,........ Calculate S17.

Charlie's Delightful Machine

Age 11 to 16
Challenge Level

You could start by exploring Shifting Times Tables to get a feel for the sequences that turn on the lights.

Try exploring just one light at a time.
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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