The 'Removing a Group' Strategy

Removing a Group is a quick strategy to derive a fact from another fact you might know. For example, 9x3 is nothing but (10 X 3) - 3. If the child remembers 10 X 3 but not 9X 3, then removing a group can help them quickly derive this in their head.

For this, removing a group is a useful skill to master so that they can call upon it when needed.

Below is one example of how removing a group is introduced to kids in Monster Math.