LCM for 15 and 28

The first method to find LCM for numbers 15 and 28 is to find Greatest Common Factor (GCF) of these numbers. Here's the formula:

LCM = (Number1 × Number2) ÷ GCF

GCF of numbers 15 and 28 is 1, so

LCM = (15 × 28) ÷ 1

LCM = 420 ÷ 1

LCM = 420

The second method to find LCM for numbers 15 and 28 is to list out the common multiples for both nubmers and pick the first which matching:

Multiples of 15: 15, 30, 45, 60, 75, 90, 105, 120, 135, 150, 165, 180, 195, 210, 225, 240, 255, 270, 285, 300, 315, 330, 345, 360, 375, 390, 405, 420, 435, 450

Multiples of 28: 28, 56, 84, 112, 140, 168, 196, 224, 252, 280, 308, 336, 364, 392, 420, 448, 476

So the LCM for 15 and 28 is 420

Another method to find LCM for numbers 15 and 28 is to list all Prime Factors for both numbers and multiply the highest exponent prime factors: