8th Graders: Introduction to Variables on Both Sides of the Equation

On Wednesday and Thursday, we discussed the problem below:

Amber and Blake bought the same amount candy.

They both received the candy in a different way.

• Amber received 2 boxes with an unknown amount plus 4 candies in a bag.

• Blake received 1 box of an unknown amount plus 10 candies in a bag.

Write an equation and solve how many pieces of candy are in each box?

Several students started out by creating two expressions, one for Amber and one for Blake.

2x + 4       and 1x + 10

A few students decided to make an equation for each student.

C= 2x + 4              and            C= 1x + 10

C= the amount of candy in one box

We then discussed one of the most important words in the problem, SAME.

Everyone remembered, same meant an equal quantity.

We also decided if C=C then,

2x + 4 = 1x + 10

Next, we decided we needed to combine like terms but this time we had to take into account the equal sign being in between the variables.

We remembered the golden rule for equations, when crossing the equal sign we must complete the inverse operation. Below is how we finished solving it.

Finally, we discussed how do we know if this makes sense. Several students suggested plugging in 6 to each of the expressions/equations above to see if the students received the same amount of candy.

They both received 16 candies. We can say x = 6 is correct because Amber received 16 and Blake received 16 or you can say because 16=16

We will continue working on solving real world problems and equations with variables on both sides of the equal sign tomorrow. We are testing on Unit 2, next Monday and Tuesday.

Have a Great Night,

Mrs. Gilliam

GO LJHS Volleyball! Beat WJHS!