Math puzzles are a great way to engage students in developing critical thinking skills. This math puzzle is an educational activity for practicing children’s math skills.

## Challenge:

The average of five numbers is 11 and the average of eight numbers is 7.75. What is the average of these 13 numbers?

### The Absolute Best Book** to ****challenge your Smart Student!**

The correct answer is 9.

The average of five numbers is 11. Therefore, their sum is:

5 × 11 = 55

The average of eight numbers is 7.75. Therefore, their sum is:

8 × 7.75 = 62

The sum of all 13 numbers is 55 + 62 = 117

Therefore, the average of these 13 numbers is:

117 ÷ 13 = 9