Solving Unknowns using the Commutative Property of Addition

This video tutorial explains how to solve for unknowns using the commutative property of addition. It begins with an introduction to fact families and demonstrates how the commutative property allows numbers to be added in any order to achieve the same sum. The tutorial provides examples, including reordering numbers for easier calculation, and highlights the limitations of applying the commutative property to subtraction. Finally, it shows how to use the property to solve for unknown addends, emphasizing the importance of recognizing common addends on both sides of an equation.

What is a key characteristic of addition equations in a fact family?

• They always result in different sums.

• They can be rearranged to get the same sum.

• They only work with even numbers.

• They are not related to subtraction equations.

In the cookie example, why do both siblings end up with the same number of cookies?

• Because the order of receiving cookies doesn't change the total.

• Because the cookies are divided equally by their mom.

• Because they both start with the same number of cookies.

• Because they both eat the same number of cookies.

How can the commutative property help in solving addition problems with unknowns?

• By rearranging numbers to simplify the equation.

• By ignoring the unknowns completely.

• By changing the numbers involved in the equation.

• By allowing subtraction to be used instead.

Why does the commutative property not apply to subtraction?

• Because subtraction is not a mathematical operation.

• Because switching numbers in subtraction changes the result.

• Because subtraction is only used in multiplication.

• Because subtraction always results in zero.

What is the result of applying the commutative property to the equation 235 + 180 = ___ + 235?

• The blank should be filled with 235.

• The blank should be filled with 180.

• The blank should be filled with 415.

• The blank should be filled with 0.