What is the rule(s) for using this shortcut to find the LCM? Greg mentions “consecutive numbers” in passing but does not say if that is a criterion. He also notes that 10 and 12 share just one factor (2), intimating that there is a condition, but he does not say it explicitly. Does any two of the numbers sharing more than one factor preclude the use of this strategy?
He explains the conditions at the end of the video. Leaving this here for anyone who wondered same.