Question

Cate submultimi cu 4 elemente are Mulțimea 123456? Plsssss cine ma poate ajuta!!!

Answer 1

$C _{6} ^{4} = \frac{6!}{4!(6-4)!}= \frac{6!}{4!2!}= \frac{4!5*6}{4!2}= \frac{30}{2}=15$