LCMof12,16,18,20=720
Hence the number can be written in the form (720×k+4) which is divisible by 7
If k=1, number =(720×1)+4=724 which is not divisible by 7
If k=2, number =(720×2)+4=1444 which is not divisible by 7
If k=3, number =(720×3)+4=2164 which is not divisible by 7
If k=4, number =(720×4)+4=2884 which is divisible by 7
Required number = 720×4+4=2884