Solving Simple Equations (1)

Group Activity 3

To solve the equation x + 5 = 9

In groups of five:

1. Put 5 bottle tops on one scale of a beam balance. Put 9 bottle tops on the other scale.
2. Put a bottle top one after the other on the scale with 5 bottle tops until the two sides balance.

1. Count the number of bottle tops added to the scale which had 5 bottle tops.
2. Discuss the results and share with other groups.

1. Count the number of bottle tops added to the scale which had 5 bottle tops.

Example 5a. Equation with sum

Solve the equation x + 6 = 10

1. x + 6 = 10
2. x + 6 – 6 = 10 – 6
   Subtract 6 from both sides​
3. x = 4

Example 5b. Equation with difference

Solve the equation y – 7 = 4

1. y – 7 = 4
2. y – 7 + 7 = 4 + 7
   Add 7 to both sides
3. ​y = 11