🧮 The mean machine

The answers, and why

1. Parachute size and fall time, made-up numbers: at "20 cm square" the 3 tries were 7, 10 and 10 seconds. What is the mean? 9 seconds. Yes. Add them: 7 + 10 + 10 = 27. There are 3 tries, so divide by 3: 27 ÷ 3 = 9.

2. Catapult arm length, made-up numbers: at "3 cm" the 3 tries were 9, 5 and 4 cm. What is the mean? 6 cm. Yes. Add them: 9 + 5 + 4 = 18. There are 3 tries, so divide by 3: 18 ÷ 3 = 6.

3. Cups that keep ice, made-up numbers: at "Glass" the 3 tries were 15, 16 and 17 minutes. What is the mean? 16 minutes. Yes. Add them: 15 + 16 + 17 = 48. There are 3 tries, so divide by 3: 48 ÷ 3 = 16.

4. Shadows through the day, made-up numbers: at "9 in the morning" the 3 tries were 10, 5 and 9 cm. What is the mean? 8 cm. Yes. Add them: 10 + 5 + 9 = 24. There are 3 tries, so divide by 3: 24 ÷ 3 = 8.

5. Toy car weight and distance, made-up numbers: at "0 pennies" the 4 tries were 4, 8, 9 and 7 cm. What is the mean? 7 cm. Yes. Add them: 4 + 8 + 9 + 7 = 28. There are 4 tries, so divide by 4: 28 ÷ 4 = 7.

6. Domino spacing and speed, made-up numbers: at "3 cm" the 4 tries were 10, 6, 9 and 7 seconds. What is the mean? 8 seconds. Yes. Add them: 10 + 6 + 9 + 7 = 32. There are 4 tries, so divide by 4: 32 ÷ 4 = 8.

7. Salt and freezing time, made-up numbers: at "Half a teaspoon" the 5 tries were 6, 7, 8, 9 and 10 minutes. What is the mean? 8 minutes. Yes. Add them: 6 + 7 + 8 + 9 + 10 = 40. There are 5 tries, so divide by 5: 40 ÷ 5 = 8.

8. Vinegar amount and balloon size, made-up numbers: at "Half a cup" the 5 tries were 15, 10, 10, 10 and 10 cm. What is the mean? 11 cm. Yes. Add them: 15 + 10 + 10 + 10 + 10 = 55. There are 5 tries, so divide by 5: 55 ÷ 5 = 11.