I have 7 different signal cards that I can flash 5 at a time. How many different signals can I make

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Originally Posted by Help09 I have 7 different signal cards that I can flash 5 at a time. How many different signals can I make Does order matter? If it doesn't, then this is a combination. $\displaystyle 7 \choose 5$$\displaystyle = \frac{7!}{5!2!} \Rightarrow 21$