Question

What is the greatest common factor of 200 and 140 

Answer 1

$200|2 \\ 100|2 \\ 50 \ |2 \\ 25 \ |5 \\ 5 \ \ |5 \\ 1 \\\\200=2^3*5^2 \\\\ 140|2 \\70 \ |2 \\ 35 \ |5 \\ 7 \ \ |7 \\1 \\\\ 140=2^2*5*7 \\\\ G.C.F(200;140)=2^2*5=20$

Answer 2

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 .