Lesson 3

The Meaning of the Mean

Est. Class Sessions: 2–3

Teacher Notes

Possible strategy: Square numbers less than 100 are
1, 4, 9, 16, 25, 36, 49, 64, 81

Numbers from the list that are multiples of 2, but not of 8: 4 and 36

The only prime factor of 4 is 2.

Prime factors of 36: 2 and 3, so the answer is 36.

I am a square number less than 100.

I am a multiple of 2, but I am not a multiple of 8.

2 is not my only prime factor.

What number am I?

Explain your strategy.