Grade 6 Expressions: Evaluating Expressions

Worked examples

Real problems from the practice worksheets, solved one step at a time.

1. Example 1

   Evaluate 5x − 10 for x = 10

   1. Replace x with 10: 5 × 10 − 10.
   2. Multiply before you add or subtract: 5 × 10 = 50, so now you have 50 − 10.
   3. Subtract: 50 − 10 = 40.
   4. So 5x − 10 = 40 when x = 10.

   Answer: 40

2. Example 2

   Evaluate 5x + 9 for x = 4

   1. Replace x with 4: 5 × 4 + 9.
   2. Multiply before you add or subtract: 5 × 4 = 20, so now you have 20 + 9.
   3. Add: 20 + 9 = 29.
   4. So 5x + 9 = 29 when x = 4.

   Answer: 29

3. Example 3

   Evaluate x − 8 for x = 10

   1. Replace x with 10: 10 − 8.
   2. Subtract: 10 − 8 = 2.
   3. So x − 8 = 2 when x = 10.

   Answer: 2