Can somebody please help me witht this Consider the set of 2

Can somebody please help me witht this?

Consider the set of 2001 numbers {1.2, ... 2001}. How many of these numbers are multiples of 3 or 4, but not 5?

Number of multiples of 3 will be: 667

Number of multiples of 4 will be: 500

Number of multiples of 12(3x4) will be: 166

Number of multiples of 15(3x5) will be: 133

Number of multiples of 20(4x5) will be: 100

Number of multiples of 60(3x4x5) will be: 33

So the numbers which are multiples of 3 or 4 but not 5 is: 667+500-166-133-100+33 = 801