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Square Grid

Age 11 to 14 Short Challenge Level:

A square is split into a 100 by 100 square grid.

100 squares in the first row are shaded, 99 in the second row, 98 in the third row, and so on.

What fraction of the whole square is shaded?


This problem is taken from the World Mathematics Championships
You can find more short problems, arranged by curriculum topic, in our short problems collection.
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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