LCM of 20 and 36

Understand the Problem

The question is asking for the least common multiple (LCM) of the numbers 20 and 36. To find the LCM, we need to determine the smallest number that is a multiple of both 20 and 36.

Answer

The least common multiple of 20 and 36 is $180$.
Answer for screen readers

The least common multiple of 20 and 36 is $180$.

Steps to Solve

  1. Find the Prime Factorization of Each Number

First, we need to factor both numbers into their prime factors.

For 20:
$$ 20 = 2^2 \times 5^1 $$

For 36:
$$ 36 = 2^2 \times 3^2 $$

  1. Identify the Highest Powers of Each Prime Factor

Next, we take each unique prime factor from the factorizations and find the highest power for each.

  • For the prime factor 2, the highest power is $2^2$.
  • For the prime factor 3, the highest power is $3^2$.
  • For the prime factor 5, the highest power is $5^1$.
  1. Multiply the Highest Powers Together

Now we multiply all the highest powers we identified:

$$ LCM(20, 36) = 2^2 \times 3^2 \times 5^1 $$

Calculating this gives:

$$ 2^2 = 4, \quad 3^2 = 9, \quad 5^1 = 5 $$

So:

$$ LCM(20, 36) = 4 \times 9 \times 5 $$

  1. Calculate the Final Product

Now we will perform the multiplication step-by-step:

First, multiply $4$ and $9$:

$$ 4 \times 9 = 36 $$

Then multiply the result by $5$:

$$ 36 \times 5 = 180 $$

So, the least common multiple of 20 and 36 is 180.

The least common multiple of 20 and 36 is $180$.

More Information

The least common multiple (LCM) helps find the smallest number that can be divided evenly by two or more numbers. Knowing how to calculate the LCM using prime factorization is a valuable tool in solving many mathematical problems, especially in fractions and ratios.

Tips

  • Failing to find the correct prime factorization, which can lead to incorrect LCM calculations.
  • Not considering all the unique prime factors or their highest powers can result in missing factors.
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