procedure to find the factors of 40: when you want to start calculating the factors start from 1. 1 is a common factor for all numbers. the following table shows the factors of 40 1 X 40 = 40 2 X 20 = 40 4 X 10 = 40 5 X 8 = 40 8 X 5 = 40 10 X 4 = 40 20 X 2 = 40 40 X 1 = 40 as shown in the above table in first row multiply 1 by number 40. from second row try for all possible numbers so that their multiplication gives 40. then the first column shows the factors of number 40 which are shown in red colour: factors of number 40: 1,2,4,5,8,10,20,40. if you divide the 40 with any one of the above factors reminder is zero