21, 42, 63, 84, 105, 126, 147, 168, 189, 210, 231, 252, 273, 294, 315, 336, 357, 378, 399.
there are 21 multiples.
21,42,63,84
There are none. The lowest multiple of 21 is 21.
21, 42, 63, 84.
21,42,63,84
21: 21, 42, 63, and 84!
21, 42, 63, 84
21, 42, 63, 84.
63
Just 63.
Just 63.
They are: 21, 42, 63 and 84