ALEXIS

1, 2 , 4 , 5 , 8 , 10 16 , 20 , 40 , 80

Multiples 1 X 80 = 80 2 X 80 = 160 3 X 80 = 240 4 X 80 = 320 5 X 80 = 400 6 X 80 = 480 7 X 80 = 560 8 X 80 = 640 9 X 80 = 720 10 X 80 = 800 Factor Tree 80    40  2    ^ \   20  2  2    ^ \ \   10  2  2  2    ^ \ \ \   5  2  2  2  2  = 2⁴ x 5