lcm of 15 and 18 — step-by-step solution

To calculate the LCM (least common multiple), we first decompose the numbers into prime factors.

15

3 \times 5

18

2 \times 3^{2}

We keep every prime factor that appears, with its greatest exponent.

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ppcm (15, 18)

3^{2} \times 5 \times 2

90