Question

using prime factorisation,find the HCF and LCM of 21,28,36,45

Answer 1

by prime factorization
$21 = 3 \times 7 \\ 28 = 2 \times 2 \times 7 \\ 36 = 2 \times 2 \times 3 \times 3 \\ 45 = 3 \times 3 \times 5$
now hcf is the common one
therefore hcf = 1 (as there are no common factor )
lcm =
$2 \times 2 \times 3 \times 3 \times 5 \times 7 \\ = 1260$
hope it helps you
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Answer 2

Answer:

Using prime factorisation