I am a common factor of 18 and 36. I am a multiple of 2 and 9. I am greater than 7. What number am I?
Factors of 18: 1, 2, 3, 6, 9, 18
Factors of 36: 1, 2, 3, 4, 6, 9, 12, 18, 36
Highest common factor of 18 and 36: 18
Multiples of 2: 2, 4, 6, 8, 10, 12, 14, 16, 18
Multiples of 9: 9, 18
Lowest common multiple of 2 and 9: 18
The number is 18.
Answer(s): 18