Factorials

problem

Factorised Factorial

Age

14 to 16

Challenge level

Weekly Problem 17 - 2010
The value of the factorial $n!$ is written in a different way. Can you work what $n$ must be?
problem

Seriesly

Age

16 to 18

Challenge level

Prove that k.k! = (k+1)! - k! and sum the series 1.1! + 2.2! + 3.3! +...+n.n!
problem

Seriesly

Age

16 to 18

Challenge level

Prove that k.k! = (k+1)! - k! and sum the series 1.1! + 2.2! + 3.3! +...+n.n!
problem

Factorial Fun

Age

16 to 18

Challenge level

How many divisors does factorial n (n!) have?
article
Binomial Coefficients

An introduction to the binomial coefficient, and exploration of some of the formulae it satisfies.
article
The Harmonic Triangle and Pascal's Triangle

The harmonic triangle is built from fractions with unit numerators using a rule very similar to Pascal's triangle.