Originally Posted by Plato That is a completely standard notation used in counting problems. It is the binomial coefficient. $\displaystyle \dbinom{N}{k}=\dfrac{N!}{k!(N-k)!}$. Please don't tell us that you do not know about factorials. sorry but i don't know about them
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at all thx but i think when using this way the result will be 378 not 336 for example of 16 , 6
Originally Posted by mido22 sorry but i don't know about them This is not a tutorial service. Originally Posted by mido22 but i think when using this way the result will be 378 not 336 for example of 16 , 6 $\displaystyle \dbinom{11}{6}-\dbinom{9}{4}=336$
Originally Posted by Plato This is not a tutorial service. ok but i get a binomial calculator and i entered N : X - y +1 and K : y and subtract from it : N : x - y -1 and k : y and then the solution will be 378 not 336
ah yes thx very much plato u r right