LCM( 380, 790 ) = 30020
Write down multiples of each number until you find the first common multiple:
The multipliers of 380 are: 380, 760, 1140, 1520, 1900, 2280, 2660, 3040, 3420, 3800, 4180, 4560, 4940, 5320, 5700, 6080, 6460, 6840, 7220, 7600, 7980, 8360, 8740, 9120, 9500, 9880, 10260, 10640, 11020, 11400, 11780, 12160, 12540, 12920, 13300, 13680, 14060, 14440, 14820, 15200, 15580, 15960, 16340, 16720, 17100, 17480, 17860, 18240, 18620, 19000, 19380, 19760, 20140, 20520, 20900, 21280, 21660, 22040, 22420, 22800, 23180, 23560, 23940, 24320, 24700, 25080, 25460, 25840, 26220, 26600, 26980, 27360, 27740, 28120, 28500, 28880, 29260, 29640, 30020, 30400, . . .
The multipliers of 790 are: 790, 1580, 2370, 3160, 3950, 4740, 5530, 6320, 7110, 7900, 8690, 9480, 10270, 11060, 11850, 12640, 13430, 14220, 15010, 15800, 16590, 17380, 18170, 18960, 19750, 20540, 21330, 22120, 22910, 23700, 24490, 25280, 26070, 26860, 27650, 28440, 29230, 30020, 30810, . . .
We can see that:
LCM( 380, 790 ) = 30020
This solution can be visualized using a Venn diagram.
The LCM is equal to the product of all the numbers on the diagram.