The first common multiple of 3 4 5 and 7 is 420.
These are the first 90 multiples of 7:714212835424956637077849198105112119126133140147154161168175182189196203210217224231238245152159266273280287294301308315322329336343350357364371378385392399406413420427434441448455462469476483490497504511518525532539546553560567574581588595602609616623630
Example: 5 and 7 List the multiples of 5. 5, 10, 15, 20, 25, 30, 35, 40... List the multiples of 7. 7, 14, 21, 28, 35, 42... The LCM is the first number that appears on both lists.
5 10 15 20 25 30 35
The first 5 common multiples are: 7x20 = 140 2x7x20 = 280 3x7x20 = 420 4x7x20 = 560 5x7x20 = 700
7,14,21,28,35
The first four multiples of five: 5, 10, 15, 20
7, 14, 21, 28, 35
7, 14, 21, 28, 35
35 and 70
35, 70, 105, etc.
The first common multiple of 3 4 5 and 7 is 420.
5 + 10+15+20=50 ans
These are the first 90 multiples of 7:714212835424956637077849198105112119126133140147154161168175182189196203210217224231238245152159266273280287294301308315322329336343350357364371378385392399406413420427434441448455462469476483490497504511518525532539546553560567574581588595602609616623630
35, 70, 105
35, 70, 105
7, 14, 21, 28, 35