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MathNet 2008-part-05 — 164 problems (EN–VI) Question 121

Math Olympiad Vault · MathNet 2008-part-05 — 164 problems (EN–VI)

Question 121

Determine the number of ways of walking from $(0,0)$ to $(5,5)$ using only up and right unit steps such that the path does not pass through any of the following points: $(1,1)$, $(1,4)$, $(4,1)$, $(4,4)$.

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