Fibonacci Day: Even Fibonacci Numbers Today is a Fibonacci Day. It is the fifth of November and five is a Fibonacci number. Let's move on from the squares of Fibonacci number...

Criss-Cross Method: Multiplication Made Easy In school, you are taught pretty early on how to do multiplication on paper. For instance: 47 x 8 That would be tough to pull off in...

How to Divide Any Number by 91 Since this is the last post of 2012, I thought I'd finish the year with a mental math technique. Before I do that though, I want to show...

Triangular Day: The Oblong Numbers I don't know if you noticed, but today is a triangular day. It is April 6th, and six is the third triangular number. You might rememb...