Question

Bài toán 5: Tìm BCNN của.

a) BCNN( 8 ; 10 ; 20)       f) BCNN(56 ; 70 ; 126)

b) BCNN(16 ; 24)             g) BCNN(28 ; 20 ; 30)

c) BCNN(60 ; 140)            h) BCNN(34 ; 32 ; 20)

d) BCNN(8 ; 9 ; 11)           k) BCNN(42 ; 70 ; 52)

e) BCNN(24 ; 40 ; 162)      l) BCNN( 9 ; 10 ; 11)

Answer 1

a) 8 = 2³

10 = 2.5

20 = 2².5

BCNN(8; 10; 20) = 2³.5 = 40

b) 16 = 2⁴

24 = 2³.3

BCNN(16; 24) = 2⁴.3 = 48

c) 60 = 2².3.5

140 = 2².5.7

BCNN(60; 140) = 2².3.5.7 = 420

d) 8 = 2³

9 = 3²

11 = 11

BCNN(8; 9; 11) = 2³.3².11 = 792

e) 24 = 2³.3

40 = 2³.5

162 = 2.3⁴

BCNN(24; 40; 162) = 2³.3⁴.5 = 3240

Answer 2

f) 56 = 2³.7

70 = 2.5.7

126 = 2.3².7

BCNN(56; 70; 126) = 2³.3².5.7 = 2520

g) 28 = 2².7

20 = 2².5

30 = 2.3.5

BCNN(28; 20; 30) = 2².3.5.7 = 420

h) 34 = 2.17

32 = 2⁵

20 = 2².5

BCNN(34; 32; 20) = 2⁵.5.17 = 2720

k) 42 = 2.3.7

70 = 2.5.7

20 = 2².5

BCNN(42; 70; 20) = 2².3.5.7 = 420

l) 9 = 3²

10 = 2.5

11 = 11

BCNN(9; 10; 11) = 2.3².5.11 = 990