84, 168, 252
The first three multiples of 42 are 42, 84 and 126.
28, 56, 84.
The three are 84, 168, and 252 - the first three multiples of 84 (14 = 2 x 7, 84 = 2 x 2 x 3 x 7) 84 = 1 x 84 , 6 x 14 168 = 2 x 84, 12 x 14 252 = 3 x 84, 18 x 14 (only the sixth multiples of 14)
42, 84 and 126
42, 84, 126
84, 168, 252
84, 168, 252
42, 84, 126
84, 168, 252
84, 168, 252
168, 336, 504
42, 84, 126