Respuesta :

bCMath
1 because only 1 can fit in all of them ( • ) means multipy so 1 • 5 =5 1•6=6 1•7=7
Write out the multiples:
5, 10, 15 etc
6, 12, 18 etc
7, 14, 21, etc

The first number that appears in all three lines will be 210.