Question
Using prime factorization, find the $HCF$ and $LCM$ of:
$12, 15, 21$
$12, 15, 21$
✓
Answer
$12 = 2 \times 2 \times 3$
$= 2^2\times 3 15$
$= 3 \times 5 21$
$= 3 \times 7$
$HCF (12, 15, 21) = 3$
$LCM (12, 15, 21)$
$= 2^2 \times 3 \times 5 \times 7 = 420$
$= 2^2\times 3 15$
$= 3 \times 5 21$
$= 3 \times 7$
$HCF (12, 15, 21) = 3$
$LCM (12, 15, 21)$
$= 2^2 \times 3 \times 5 \times 7 = 420$
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