Question

What is the smallest odd number with four different prime factors?

Answer 1

Obviously the smallest odd number we are looking for will have the SMALLEST four prime factors. 

The smallest four prime numbers are 2,3,5,7. The lowest multiple of this is 2*3*5*7 = 210 But this is an even number! 

So let's remove 2, and use the next prime number: 3,5,7,11. The lowest multiple of these is 3*5*7*11 = 1155.

Answer 2

The answer is 210 since the numbers are (2x3x5x7)