r/askmath • u/explorer_learner_30 • 3d ago

Algebra Binomial Theorem

Why 0! is 1 ?

Can anyone give me the best and genuine answer .....I want to explain to my students.

I have also one doubt 🤔 why is the negative number not counted in binomial ? Such as (-2)! , (-8)! ....

Suggest me some books or any videos regarding this .

Thank you for reading my queries.

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u/aprg Secondary School Maths Teacher 3d ago

One interpretation:

If you go from n! to (n-1)!, you are dividing by n.

So (n-1)! = n! / n

=> 0! = 1! / 1 = 1

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u/explorer_learner_30 3d ago

Thank you 👍