Quater-imaginary Base - Addition and Subtraction

Addition and Subtraction

It is possible to add and subtract numbers in the quater-imaginary system. In doing this, there are two basic rules that have to be kept in mind:

1. Whenever a number exceeds 3, subtract 4 and "carry" −1 two places to the left.
2. Whenever a number drops below 0, add 4 and "carry" +1 two places to the left.

Or for short: "If you add four, carry +1. If you subtract four, carry -1". This is the opposite of normal long addition, in which a "carry" in the current column requires adding 1 to the next column to the left, and a "borrow" requires subtracting. In quater-imaginary arithmetic, a "carry" subtracts from the next-but-one column, and a "borrow" adds.