# The "Unsolvable" 2019 PSLE Mathematics Question

Updated: Dec 29, 2020

By now, most readers would have read about the challenging mathematics question that caused a furore amongst worried parents.

In case you have not tried solving it, give it a go (or ask your child to)!

Why is this question difficult?

The most commonly-cited reason is that the progression of the number of white triangles and grey triangles in the table do not appear to follow an easily discernible pattern.

Check your answer by watching the video solution - we've presented two of them. The more efficient method requires imagination and visualisation while the other requires some understanding of basic arithmetic progression methods.

Here's Ahsan (who'd just completed his PSLE at the time of recording) giving the question a go and explaining the solution in his own words.

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