The diagram illustrates the formula: 1 + 3 + 5 + ... + (2n - 1) = n² Use the diagram to show that any odd number is the difference of two squares.
How many zeros are there at the end of the number which is the
product of first hundred positive integers?
Find the five distinct digits N, R, I, C and H in the following
(This problem was inspired by Rachel Galley's work on the
problem called Giants
in the June 1999 Six.)