210 is not a multiple of 420. 420 is a multiple of 210.
210, 420
210, 420, 630, 840 . . .
There are an infinite number of multiples of any number. A multiple of a number is the product of that number multiplied by any integer other than zero. The multiples of 210 are 210, 420, 630, 840, 1050, and continuing on to an infinite quantity of numbers that can be divided evenly by 210.
420
210, 420, 630, 840, 1050 Five common multiples. Only one can be least.
105, 210, 315, 420, 525, 630
70, 140, 210, 280, 350, 420, 490
210, 420, 630, 840, 1050, 1260.
210, 420, 630 and so on.
67
210, 420, 630, 840, 1050, 1260, 1470, 1680, 1890, . . . (to infinity).
Multiples of 14: 14, 28, 42 and so on. Multiples of 15: 15, 30, 45 and so on. Common multiples include 210, 420, 630 and so on.