Question Video: Finding a Value of an Unknown in Algebraic Equations Using the Commutative Property Mathematics • 6th Grade

Video Transcript

If 𝑦 over five plus 45 is equal to 45 plus three over five, what is the value of 𝑦?

Of course, we could take this equation and try to solve algebraically. To do that, we would try to get 𝑦 by itself. If we subtract 45 from both sides of our equation, on both sides, we have 45 minus 45, which is zero. And the remaining part of the equation is 𝑦 over five is equal to three over five.

Multiplying both sides of the equation by five, because five over five is one, 𝑦 is equal to three. This is illustrating the commutative property of addition, which tells us that 𝑎 plus 𝑏 is equal to 𝑏 plus 𝑎. And that means it’s possible that we could have said 𝑦 over five is equal to three over five based on the commutative property of addition.

And therefore, 𝑦 is equal to three. Both methods give us a final answer for the value of 𝑦 of three.