Problems on H.C.F and L.C.M - General Questions

Find the L.C.M. of 5, 31 and 26.

Find the greatest number that divides 249, 417, 129 leaving the same remainder in each case.

Find the H.C.F. of 12, 54 and 30.

What is the least number which, when divided by 10, 4, 16, leaves a remainder 3 in each case?

Find the greatest number that divides 16, 61, 55 leaving the same remainder in each case.