\(18=2.3^2\)

\(45=3^2.5\)

\(54=2.3^3\)

\(ƯCLN=3^2=9\)

\(BCNN=2.3^3.5=270\)

a: B(6)={6;12;18;24;...}

B(9)={9;18;27;...}

B(12)={12;24;36;...}

Ư(30)={1;-1;2;-2;3;-3;5;-5;6;-6;10;-10;15;-15;30;-30}

Ư(45)={1;-1;3;-3;5;-5;9;-9;15;-15;45;-45}

Ư(60)={1;-1;2;-2;3;-3;4;-4;5;-5;6;-6;10;-10;12;-12;15;-15;20;-20;30;-30;60;-60}

b: \(36=2^2\cdot3^2;48=2^4\cdot3\)

=>ƯCLN(36;48)=\(2^2\cdot3=12\)

\(24=2^3\cdot3;28=2^2\cdot7;36=2^2\cdot3^2\)

=>ƯCLN(24;28;36)=\(2^2=4\)

c: \(6=3\cdot2;8=2^3\)

=>BCNN(6;8)=\(2^3\cdot3=8\cdot3=24\)

\(8=2^3;9=3^2;72=2^3\cdot3^2\)

=>BCNN(8;9;72)=\(2^3\cdot3^2=72\)

d: \(15=3\cdot5;54=3^3\cdot2\)

=>BCNN(15;54)=\(3^3\cdot2\cdot5=27\cdot10=270\)

=>BC(15;54)={270;540;810;1080;...}

=>Các bội chung nhỏ hơn 1000 của 15 và 54 là 270;540;810

BCNN(15;54)=270

BC(15;54)=B(270)={270;540;810}

BCNN(15;54)=270

BC(15;54)=B(270)={270;540;810}

54=2x \(3^3\)

36= \(2^2\)x \(3^2\)

BCNN ( 54 , 36 ) =  \(3^3\)x \(2^2\)=108

Vậy BCNN ( 54, 36) = 108

CHÚC BẠN HỌC TỐT

54 = 2x \(3^3\)

36=\(2^2\)x \(3^2\)

BCNN ( 54 , 36) = 2 x \(3^2\)= 18 

Vậy BCNN ( 54 , 36 )= 18

CHÚC BẠN HỌC GIỎI

54=2.3^3

180=2^2.3^2.5

500=2^2.5^3

=>BCNN(54;180;500)=2^2.3^3.5^3=13500

a) Ta có: 21 = 3.7;  98 = 2.7²

=> ƯCLN(21, 98) = 7 ; BCNN(21, 98) = 2.3.7² = 294

b) Ta có: 36 = 2².3², 54 = 2.3³

ƯCLN(36, 54) = 2.3² = 18; BCNN(36, 54) = 2².3³ = 108.

36 = 2².3²

54 = 2.3³

ƯCLN(36; 54) = 2.3² = 18

BCNN(36; 54) = 2².3³ = 108

--------

40 = 2³.5

72 = 2³.3²

90 = 2.3².5

ƯCLN(40; 72; 90) = 2

BCNN(40; 72; 90) = 2³.3².5 = 360

gn

a) Ta có:

\(21=3\cdot7\\98=2\cdot7^2\)

Khi đó, ta được: 

\( UCLN(21,98)=7\)

\(BCNN(21,98)=2\cdot3\cdot7^2=294\)

b) Ta có:

\(36=2^2\cdot3^2\\54=2\cdot3^3\)

Khi đó, ta được:

\(UCLN\left(36,54\right)=2\cdot3^2=18\)

\(BCNN\left(36,54\right)=2^2\cdot3^3=108\)