# Bino-Combi-Turals

Discrete Mathematics Level 5

$\large \sum_{k=0}^{10} (-1)^{k} \binom{20}{2k} = \, ?$

 Notation: $$\dbinom MN$$ denotes the binomial coefficient, $$\dbinom MN = \dfrac{M!}{N!(M-N)!}$$.

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