This collection of images focusses on the odd and even LAST DIGITS of decimal numbers. The importance of Last Digits is:-
- the distinction between odd [1 3 5 7 9] and even [0 2 4 6 8];
- the identification as a possible Prime Number [only sum not product]: 1 3 7 9.
In search of a solution to the Prime Number problem, we keep 1 3 7 9 under scrutiny as Last Digits.
In the Pyramid shape, columns alternate between odd and even.
Rows offer predictable growing intervals in series of five digits.