Counting shapes hidden inside a figure

A drawing of overlapping lines contains far more triangles or squares than the ones that are drawn as separate cells. Count by size - all the smallest first, then the ones made of four cells, and so on - so that no size gets forgotten.

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LearnWhat it is, how to spot it, a worked example, and where it goes wrong.
Practice — 3-point ladder1 problem. Three in a row finishes it.0/3 in a row · 0/1 solved
Practice — 4-point ladder1 problem. Three in a row finishes it.0/3 in a row · 0/1 solved
Practice — 5-point ladder1 problem. Three in a row finishes it.0/3 in a row · 0/1 solved
Skill quizFinish every ladder that has problems first.Finish the ladders above first

Before and after

Needs first

CNT-04Casework CNT-12Counting by position (sliding window)

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Nothing yet. No other skill in the Atlas lists this one as a prerequisite.

In official papers

No indexed official paper question has been tagged with CNT-13 yet. The index grows one paper at a time, and it records only question numbers, point values and our own skill tags — never the problems themselves.

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