Answer:
38= 1, 2, 19 and 38
39= 1,3, 13 and 39
40= 1,2,4,5,8,10,20 and 40
common factors is 1
to know the factors in commas without finding the factor is to simply divide the number by each factor gotten, take for example i have 38 as the number and i have gotten 1, 2.
38 divided by 1 equals 38
38 divided by 2 equals 19
so they are the factors
Explanation: