Giúp e vớiii éc o éccc

Bài 12:

a/ BC ( 10;12;15 ) ={ 0; 60; 120; 180; 240; 180; 240; 300; 360; 420; 480; 540; 600;...}

b/ BC ( 28;56;560 ) ={ 560; 1120; 1680; 22440; 2800; 3360; 3920; ...}

c/ BC ( 24;40;168 ) ={ 840; 1680; 2520; 3360; 4200; 5040; 5880; ...}

d/ BC ( 100;120;140 ) ={ 4200; 8400; 12600; 16800; 21000; 25200; ...}

Bài 13 :

a/ ƯCLN ( 16;24 ) = {8}

b/ ƯCLN ( 12;20 ) = {4}

c/ ƯCLN ( 40;60 ) = {20}

d/ ƯCLN ( 32;80 ) = {16}