What is the greatest common factor of 200 and 140

The factors of  200  are  1,  2,  4,  5,  8,  10,  20,  25,  40,  50,  100, and  200 .

The factors of  140  are  1,  2,  4,  5,  7,  10,  14,  20,  28,  35,  70, and  140 .

The factors common to both are  1,  2,  4,  5,  10, and  20 .

The greatest one of those is  20 .

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