- Current Version: 22.214.171.124
- Last Updated: 2/13/2013
- OS Require: Windows Phone 8,Windows Phone 7.5
Casting Out Nines
Casting out nines is a method for checking your answer is correct. It provides a quick method for checking an answer. Practising casting out nines (also known as the digit sum method) you will become very fast at ensuring your answer is always correct and never make a silly mistake again.
The process involves adding up individual digits of the numbers on both sides of the equation. If the numbers are the same, then the answer is correct.