The GCF is 80.
The common multiples of 16 and 20 are 80, 160, 240, 320, 400, 480, 560, 640, and so on.
320, 640, 960, 1280, 1600, 1920 and so on.
The GCF is 30.
The GCF is 12.
80 (240/80 = 3 and 320/80 = 4)
The GCF is 320.
The GCF is 80.
The GCF is 80.
80, 160, 240, 320, 400, 480, 560, 640, 720 +80 . . .
80, 160, 240, 320, 400, 480, 560, 640, 720, 800, 880, . . .
80 160 240 320 400 480 560 640 720 800
80, 160, 240, 320, 400, 480, 560, 640, 720, 800.
80, 160, 240, 320, 400, 480, 560, 640, 720, 800
The GCF is 10.
80, 160, 240, 320, 400, 480, 560, 640, 720, 800, 880.
How about: 2*320 = 640