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2006 xIMC keystage2-EMIC team Question 9

xIMC · 2006 xIMC keystage2-EMIC team

Question 9

Place any four digits from $1$ to $5$ in a $2\times2$ square. In each row the left digit exceeds the right; in each column the top digit exceeds the bottom. How many arrangements are there? Two examples are shown in the original figure.

Question illustration