Lost Sums

Worksheet Description

This worksheet presents two columns of addition equations, where the left column contains complete equations and the right column lists equations with only one addend and the equals sign, indicating that the sum is to be found. Students are expected to draw lines between equations in the left column and their corresponding commutative pairs in the right column. The task utilizes the commutative property of addition to emphasize that the order in which two numbers are added does not affect the sum. An example is provided on the sheet, showing a dotted line connecting one pair of equations, guiding students on how to complete the task.

The worksheet is designed to teach students the commutative property of addition, demonstrating that addends can be swapped while still obtaining the same total. It allows students to practice recognizing equivalent equations regardless of the order of their terms. This reinforces the understanding that addition is non-directional, a foundational arithmetic concept that is critical for developing flexibility in mathematical thinking. Furthermore, the activity helps students build confidence in solving addition problems and prepares them for more advanced math topics that rely on this property.