180, 360, 540, 720, 900 +180 . . .
60, 120, and all multiples of 60 thereafter.
The smallest number that 8 or 12 or 20 will all go in to is 120 120 = 20 x 6 = 12 x 10 = 8 x 15 as there is then no number that goes into 6 and 10 and 15 equally.
9 has no common factors with 20- sorry!
The LCM of the given three numbers is 60
429,294
they all go into 24
All multiples of 42.
42
Any multiple of 60. There are an infinite number of them.
14
Let number be x Then x - (-14) = 20 or x + 14 = 20 or x = 20 -14 or x = 6 Verification: 6 - (-14) = 6 + 14 = 20
They are 1, 2, 7 and 14.