Highest Common Factor

Example 1:

$$ \textup{Find the H.C.F. of } 24 \textup{ and } 42 $$

Solution:

$$ \begin{array}{|l} \llap{2~~~~} 24,42 \\ \hline \llap{3~~~~} 12,21 \\ \hline \phantom{x}4,7 \end{array} $$ $$ \textup{H.C.F. }=2×3$$ $$ \textup{H.C.F. }=6$$

Example 2:

$$ \textup{Find the H.C.F. of } 220 \textup{ and } 275 $$

Solution:

$$ \begin{array}{|l} \llap{5~~~~} 220,275\\ \hline \llap{11~~~~} 44,55\\ \hline \phantom{x}4,5 \end{array} $$ $$ \textup{H.C.F. }=5×11$$ $$ \textup{H.C.F. }=55$$

Example 1:

$$ \textup{Find the H.C.F. of } 60 \textup{ and } 84 $$

Solution:

$$ \begin{array}{|l} \llap{2~~~~} 60,84 \\ \hline \llap{2~~~~} 30,42 \\ \hline \llap{3~~~~} 15,21 \\ \hline \phantom{x}5,7 \end{array} $$ $$ \textup{H.C.F. }=2×2×3$$ $$ \textup{H.C.F. }=12$$

Example 2:

$$ \textup{Find the H.C.F. of } 126 \textup{ and } 294 $$

Solution:

$$ \begin{array}{|l} \llap{2~~~~} 126,294 \\ \hline \llap{3~~~~} 63,147 \\ \hline \llap{7~~~~} 21,49 \\ \hline \phantom{x}3,7 \end{array} $$ $$ \textup{H.C.F. }=2×3×7$$ $$ \textup{H.C.F. }=42$$

Example 1:

$$ \textup{Find the H.C.F. of } 420 \textup{ and } 660 $$

Solution:

$$ \begin{array}{|l} \llap{2~~~~} 420,660 \\ \hline \llap{2~~~~} 210,330 \\ \hline \llap{3~~~~} 105,165 \\ \hline \llap{5~~~~} 35,55 \\ \hline \phantom{x}7,11 \end{array} $$ $$ \textup{H.C.F. }=2×2×3×5$$ $$ \textup{H.C.F. }=60$$

Example 2:

$$ \textup{Find the H.C.F. of } 252 \textup{ and } 468$$

Solution:

$$ \begin{array}{|l} \llap{2~~~~} 252,468 \\ \hline \llap{2~~~~} 126,234 \\ \hline \llap{3~~~~} 63,117\\ \hline \llap{3~~~~} 21,39 \\ \hline \phantom{x}7,13 \end{array} $$ $$ \textup{H.C.F. }=2×2×3×3$$ $$ \textup{H.C.F. }=36$$