1、 The greatest common divisor of 840 and 1764 can be obtained by division 2、 Find the greatest common divisor of 440 and 556 by phase change subtraction

1、 The greatest common divisor of 840 and 1764 can be obtained by division 2、 Find the greatest common divisor of 440 and 556 by phase change subtraction

1764=840*2+84;840=84*10+0;
So the greatest common divisor is 84
First, divide 440 and 556 by 4 to get 110 and 139
139=110+29；
110=29+81；
81=29+52；
52=29+23；
29=23+6；
23=6+17；
17=6+11；
11=6+5；
6=5+1；
5=1+4；
4=1+3；
3=1+2；
2=1+1；
So the greatest common divisor of 139 and 110 is 1
So the greatest common divisor of 440 and 556 is 4
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