If L=lcm(a,b)L = \text{lcm}(a, b)L=lcm(a,b) and MMM is any positive common multiple of aaa and bbb, which must be true?
M=LM = LM=L
L∣ML \mid ML∣M
M∣LM \mid LM∣L
L+M=a⋅bL + M = a \cdot bL+M=a⋅b