Question

Using prime factorization, find the HCF and LCM of:
$21,28,36,45$

Answer 1

$21=3\times 7=2^0\times 3\times 5^0\times 7$

$28=2^2\times 7=2^2\times 3^0\times 5^0\times 7$

$36=2^2\times 3^2=2^2\times 3^2\times 5^0\times 7^0$

$45=3^2\times 5=2^0\times 3^2\times 5\times 7^0$

From the above

$HCF=2^0\times 3^0\times 5^0\times 7^0=1$

$LCM=2^2\times 3^2\times 5\times 7=1260$