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**chinkmeista** I'm reading my textbook, but i don't understand the difference between $\displaystyle ^n\mathrm{C}_r$ and $\displaystyle ^n\mathrm{P}_r$? All it says that for $\displaystyle ^n\mathrm{P}_r$ the order matters and for $\displaystyle ^n\mathrm{C}_r$,the order doesn't matter but i'm not sure what this means. I can do the working out etc. but I'm just worried when i come across a worded problem, i'm not sure which one to apply?

if anyone can explain, il be super grateful!