Simply create a factor table for each number. Highlight the highest factor that is the same across all 3 numbers. This would be the GCF It would have to be 10.
The greatest common factor for 110,40, and 120 is 10. 110 factors: 1,2,5,10,11,22,55,110. 40 factors: 1,2,4,5,8,10,20,40. 120 factors: 1,2,3,4,5,6,8,10,12,15,20,24,30,40,60,120.
