Respuesta :

 writing each one  in prime factors:_
1
2
3
2 * 2
5
2 * 3
7
2* 2 * 2
3 * 3
2 * 5

so the smallest  number ( the L.C.M)  = 1*2*2*2*3*3*5*7  =  2520

The answer is 2520.