Ta có: \(36=2^2\cdot3^2\)
\(90=2\cdot3^2\cdot5\)
Do đó: \(UCLN\left(36;90\right)=2\cdot3^2=18\)
Vậy: UCLN(36;90)=18
Ư(36) ={ 1; 36; 18; 2; 3; 12; 4; 9; 6 }
Ư(90) = { 1; 90; 3; 30; 2; 45; 18; 5; 15; 6; 9; 10 }
ƯC ={ 1; 2; 3; 6; 18; 9 }
ƯCLN : 18