LCM( 50, 65, 70 ) = 4550
Write down multiples of each number until you find the first common multiple:
The multipliers of 50 are: 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, 1000, 1050, 1100, 1150, 1200, 1250, 1300, 1350, 1400, 1450, 1500, 1550, 1600, 1650, 1700, 1750, 1800, 1850, 1900, 1950, 2000, 2050, 2100, 2150, 2200, 2250, 2300, 2350, 2400, 2450, 2500, 2550, 2600, 2650, 2700, 2750, 2800, 2850, 2900, 2950, 3000, 3050, 3100, 3150, 3200, 3250, 3300, 3350, 3400, 3450, 3500, 3550, 3600, 3650, 3700, 3750, 3800, 3850, 3900, 3950, 4000, 4050, 4100, 4150, 4200, 4250, 4300, 4350, 4400, 4450, 4500, 4550, 4600, . . .
The multipliers of 65 are: 65, 130, 195, 260, 325, 390, 455, 520, 585, 650, 715, 780, 845, 910, 975, 1040, 1105, 1170, 1235, 1300, 1365, 1430, 1495, 1560, 1625, 1690, 1755, 1820, 1885, 1950, 2015, 2080, 2145, 2210, 2275, 2340, 2405, 2470, 2535, 2600, 2665, 2730, 2795, 2860, 2925, 2990, 3055, 3120, 3185, 3250, 3315, 3380, 3445, 3510, 3575, 3640, 3705, 3770, 3835, 3900, 3965, 4030, 4095, 4160, 4225, 4290, 4355, 4420, 4485, 4550, 4615, . . .
The multipliers of 70 are: 70, 140, 210, 280, 350, 420, 490, 560, 630, 700, 770, 840, 910, 980, 1050, 1120, 1190, 1260, 1330, 1400, 1470, 1540, 1610, 1680, 1750, 1820, 1890, 1960, 2030, 2100, 2170, 2240, 2310, 2380, 2450, 2520, 2590, 2660, 2730, 2800, 2870, 2940, 3010, 3080, 3150, 3220, 3290, 3360, 3430, 3500, 3570, 3640, 3710, 3780, 3850, 3920, 3990, 4060, 4130, 4200, 4270, 4340, 4410, 4480, 4550, 4620, . . .
We can see that:
LCM( 50, 65, 70 ) = 4550
This solution can be visualized using a Venn diagram.
The LCM is equal to the product of all the numbers on the diagram.