ƯC (35;77)
Ta có :
35={1:5:7:35}
77={1:7:11:77}
= ƯC (35:77) ={1;7}
BC (18;30)
Ta có:
18 = {0;18;36;54;72;90;........}
30 ={0;30;60;90;120;150;...........}
= BC (18;30) = {0;90;................}
ƯCLN (125;75)
Ta có:
125 = 5^3
75 = 3.5^2
= ƯCLN (125;75) = 5^2 = 25
BCNN (13;29)
Ta có:
13 = 13
29 = 29
= BCNN (13;29) = 13.29 = 377