article

### Binomial Coefficients

An introduction to the binomial coefficient, and exploration of some of the formulae it satisfies.

article
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Binomial Coefficients

An introduction to the binomial coefficient, and exploration of some of the formulae it satisfies.

problem
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Factorised Factorial

Weekly Problem 17 - 2010

The value of the factorial $n!$ is written in a different way. Can you work what $n$ must be?

The value of the factorial $n!$ is written in a different way. Can you work what $n$ must be?

problem
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Fac-Finding

Favourite

Lyndon chose this as one of his favourite problems. It is
accessible but needs some careful analysis of what is included and
what is not. A systematic approach is really helpful.

problem
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Powerful factorial

6! = 6 x 5 x 4 x 3 x 2 x 1. The highest power of 2 that divides
exactly into 6! is 4 since (6!) / (2^4 ) = 45. What is the highest
power of two that divides exactly into 100!?

problem
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Factorial

How many zeros are there at the end of the number which is the
product of first hundred positive integers?