Grade 5 Expressions: Evaluating Expressions

Worked examples

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

1. Example 1

   Evaluate x + 7 for x = 3

   1. Replace x with 3: 3 + 7.
   2. Add: 3 + 7 = 10.
   3. So x + 7 = 10 when x = 3.

   Answer: 10

2. Example 2

   Evaluate 5x + 8 for x = 6

   1. Replace x with 6: 5 × 6 + 8.
   2. Multiply before you add or subtract: 5 × 6 = 30, so now you have 30 + 8.
   3. Add: 30 + 8 = 38.
   4. So 5x + 8 = 38 when x = 6.

   Answer: 38

3. Example 3

   Evaluate 5x − 9 for x = 6

   1. Replace x with 6: 5 × 6 − 9.
   2. Multiply before you add or subtract: 5 × 6 = 30, so now you have 30 − 9.
   3. Subtract: 30 − 9 = 21.
   4. So 5x − 9 = 21 when x = 6.

   Answer: 21