Q.11 Find the LCM of the following numbers in which one number is the factor of the other.
(a) 5, 20
(b) 6, 18
(c) 12, 48
(d) 9, 45
What do you observe in the results obtained?

(a) 5, 20 $$ \begin{array}{|l} \llap{5~~~~} 5, 20 \\ \hline 1, 4 \end{array} $$ LCM = 5×4 = 20
(b) 6, 18
$$ \begin{array}{|l} \llap{2~~~~} 6, 18 \\ \hline \llap{3~~~~} 3, 9 \\ \hline 1, 3 \end{array} $$ LCM = 2 × 3 × 3 = 18
(c) 12, 48
$$ \begin{array}{|l} \llap{2~~~~} 12, 48 \\ \hline \llap{2~~~~} 6, 24 \\ \hline \llap{3~~~~} 3, 12 \\ \hline 1, 4 \end{array} $$ LCM = 2 × 2 × 3 × 4 = 48
(d) 9, 45
$$ \begin{array}{|l} \llap{3~~~~} 9, 45 \\ \hline \llap{3~~~~} 3, 15 \\ \hline 1, 5 \end{array} $$ LCM = 3 × 3 × 5 = 45