800, 1600, 2400, 3200, 4000, 4800, 5600, 6400, 7200, 8000, 8800, 9600, 10400, 11200, 12000.
The first five multiples of 5 are 5, 10, 15, 20 and 25. For them to be common, they need to be compared to another set of multiples.
Multiples of 800
The first 15 multiples of 160: 160, 320, 480, 640, 800, 960, 1120, 1280, 1440, 1600, 1760, 1920, 2080, 2240, 2400 . . . ∞
The first five multiples are: 11 22 33 44 and 55
400 800 1200 multiples of 4
800, 1600, 2400, 3200, 4000, 4800, 5600, . . .
multiples of 400: 400, 800, 1200, 1600, 2000, 2400, ...
They are: 4 8 12 and 16
multiples of 11 11,22,33,44,55,,66,77,88,99 multiples of 15 15,30,45,60,75,90
Multiples of 15 include 15, 30 and 45. For them to be common, they need to be compared to another set of multiples.
400, 600, 800.
The multiples of 15 are: 15 and it could just go on and on forever