Hands on Equations (Day 4)

We continued working with the Subtraction Property of Equality today using the Hands-On Equations manipulatives.  Yesterday our focus was using the property with our variable "x" (also known as the pawns).  Today, we continued this portion of the property, but we also used the property with our constants, which are the known numbers (the number cubes).  For example:

• Pull down one pawn from each side of the equation leaving:

3x + 2 = 2x +9

• Pull down another pawn from each side of the equation leaving:

2x + 2 = x + 9

• Pull down another pawn from each side of the equation leaving:

x + 2 = 9

• Now pull down 2 from each side of the equation leaving:

x = 7

• We have just solved for x.  Now, we replace our manipulatives to show the original equation:

4x + 2 = 3x +9

• Replace "x" with the value "7" and solve:

4 x 7 + 2 = 3 x 7 + 9

28 + 2 = 21 + 9

30 = 30

I have made a short video demonstrating this lesson, just follow the link:  Hands-On Equations Day 4.