Need help with some math

I probably learned this in 5th grade but somehow I'm stumped. Let me try to make this simple. If I have a chart with the numbers 1 through 25 and I have to select 5 numbers at random (can't pick the same number twice), how many different combinations of numbers could be chosen?

25 choose 5 or 25C5 = 25!/5!20! = 25*24*23*22*21/(5*4*3*2*1)

= 53,130
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Finding the number of combinations for n things taken r at a time:

= n! / (n - r)!r!
= 25! / (25 - 5)!5!
= 25! / 20!5!
= [25 * 24 * 23 * 22 * 21] / [5 * 4 * 3 * 2 * 1]
= 5 * 6 * 23 * 11 * 7
= 53130 (Answer)

There are 53130 combinations.
Have a good day.