b) 12 = 2^2 × 3
24 = 2^3 × 3
36 = 2^2 × 3^2
C.m.m.m.c.(12,24,36) = 2^3 × 3^2 = 8 × 9 = 72
e) 16 = 2^4
20 = 2^2 × 5
48 = 2^4 × 3
C.m.m.m.c.(16,20,48) = 2^4 × 3 × 5 = 240
h) 18 = 2 × 3^2
45 = 3^2 × 5
56 = 2^3 × 7
C.m.m.m.c.(18,45,56) = 2^3 × 3^2 × 5 × 7 = 8×9×5×7 = 2520
k) 450 = 2 × 3^2 × 5^2
900 = 2^2 × 3^2 × 5^2
1350 = 2 × 3^3 × 5^2
C.m.m.m.c.(450,900,1350) = 2^2 × 3^3 × 5^2 = 4 × 27 × 25 = 2700
n) 120 = 2^3 × 3 × 5
360 = 2^3 × 3^2 × 5
720 = 2^4 × 3^2 × 5
C.m.m.m.c.(120,360,720) = 2^4 × 3^2 × 5 = 720