Key learning points

1. If one addend is increased and the other is decreased by the same amount, the sum stays the same.
2. If the minuend and subtrahend are changed by the same amount, the difference stays the same.

Keywords

• Peimeter - The perimeter is the distance around a 2D shape.

• Expression - An expression contains one or more values, where each value is separated by an operator.

• Area - Area is the measurement of a flat surface. It measures 2D space.

Common misconception