Bài 1:
a) 16 = $2^{4}$
24 = $2^{3}$ . 3
$ƯCLN_{(16; 24)}$ = $2^{3}$ = 8
$ƯC_{(16; 24)}$ = {1; 2; 4; 8}
c) 24 = $2^{3}$ . 3
84 = $2^{2}$ . 3 . 7
180 = $2^{2}$ . $3^{2}$ . 5
$ƯCLN_{(24; 84; 180)}$ = $2^{2}$ . 3 = 12
$ƯC_{(24; 84; 180)}$ = { 1; 2; 3; 6; 12 }
d) 144 = $2^{4}$ . $3^{2}$
120 = $2^{3}$ . 3 . 5
135 = $3^{3}$ . 5
ƯCLN ( 144; 120; 135 )=3
ƯC ( 144; 120; 135 ) = { 1; 3 }