# What does this mean?

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When a math book says, "Write the value of 5!."

What does it mean when there is an exclamation mark at the end of a number? This is Abeka Math 7, btw.

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It means they're really excited about math?

Sorry, I have no idea. :D

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It's a factorial equation. The value is 5*4*3*2*1, or 120.

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I think it is a special function. I have not researched it but I seem to remember that it is shorthand for 5x4x3x2x1.

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I studied in France for a year and there would be ! marks after numbers. I don't quite remember what it meant, but something along the lines of the ! meaning to include all the preceding numbers. So 5! would mean 5, 4, 3, 2, and 1. So I guess the value would be 5+4+3+2+1. It was a shortcut to writing it out. I've never seen it in any math book here, though, so it could mean something completely different. Plus, that was quite a few years ago and my memory isn't what it used to be! Who knew math was done differently in different countries? They also used open-ended parentheses, like (5+1(. What is that??? I didn't do well in math over there :tongue_smilie:

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It's a factorial equation. The value is 5*4*3*2*1, or 120.

:iagree:

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It's a factorial equation. The value is 5*4*3*2*1, or 120.

:iagree:

Factorial.

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Ahh, thank you all! :D

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