The Math Meridian
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GCF and LCM

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Learn it GCF: the largest number that divides all the numbers. LCM: the smallest number that all the numbers divide into. For two numbers, $\text{LCM} = a \times b \div \text{GCF}$.

Example: Find the GCF and LCM of 18 and 24.

  1. $18 = 2 \times 3^2$ and $24 = 2^3 \times 3$.
  2. GCF: shared primes with the smaller powers: $2 \times 3 = 6$.
  3. LCM: $18 \times 24 \div 6 = 72$.

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