3
4
9
6
Answer is Right!
Answer is Wrong!
The missing number is 6.
The numbers in the sequence are all multiples of 3, except for 1. This is because 1 is the only number that is not divisible by 3.
The numbers in the sequence are also all odd numbers, except for 4. This is because 4 is the only even number that is divisible by 3.
Therefore, the missing number must be an odd number that is divisible by 3. The only number that fits this description is 6.