In this activity, we will look at **equations** with two unknowns.

* a *and

*stand for two numbers, which could be different or the same.*

**b**

Look at this equation.

**a + b = 8**

It tells you that * a added to b is 8*.

We are looking for any two numbers that **add to 8** in order to satisfy (fit) the equation.

If * a is 6, b will be 2*.

If a = 2, b = 6

If *a = 4½, b = 3½*

**Example**

**a - b = 7**

Which of these solutions satisfy the equation?

a = 7, b = 0

a = 0, b = 7

a = 10, b = 3

a = 10¾, b = 3¾

**Answer**

Put the given pairs into the equation to see if * a - b is 7* or not.

a = 7, b = 0 | fits because 7 - 0 = 7 |

a = 0, b = 7 | does not fit because 0 - 7 = -7 (not 7) |

a = 10, b = 3 | fits because 10 - 3 = 7 |

a = 10¾, b = 3¾ | fits because 10¾ - 3¾ = 7 |