No, to get a total you add, not multiply.
84 is the LCM (least common multiple) of 3, 4, and 7.
12
LCM of 3 and 4 is 12.Multiply them. Get 12.
The LCM is 12.
12
If X is a multiple of 4, it will be the LCM.
36
I assume you mean LCM, least common multiple. The least common multiple of 3 and 4 is 12. 12 is a multiple of 3. 12 is a multiple of 4. No smaller number is a multiple of both 3 and 4.
The Lowest Common Multiple of 3 and 4 is 12. 3*4=12 4*3=12
12 is the smallest multiple of 3 and 4.
5
The smallest multiple of 3 4 and 5 is 60.