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Total float = LS-ES or LF-EF
The total float time is for the same activity
Free float time is for two immediately adjacent activities
Free activity time = the earliest start time of the successor activity - the latest end time of the predecessor activity
Total time difference = LS-ES of the same activity
LS: the latest start, ES: the earliest start
eg: (The following excerpts are excerpted from the Internet)
What is the formula for calculating free time difference? What is the formula for calculating free time difference? There is a regulatory question about the calculation of free time difference. It is known that a project has follow-up work. The earliest start time of the following work is the 9th day, the earliest start time of this work is the 4th day, the latest start time is the 10th day, and the duration of the work is 3 days. I know that the total time difference = 10-4 = 6, then Why is the free time 2 days and how to get it
The concept of free time difference can be found in the definition of single time difference in P130, or in other words, free time difference (free float)
It refers to the maneuver time that can be used for this work without affecting the earliest start time of the subsequent work.
That is: for a job with successor tasks, the free time difference is equal to the minimum value of the difference between the earliest start time of all successor tasks of the job minus the earliest completion time of the job (earliest start time + duration).
Take this question as an example: FFi=ESj-ESi-DUi=9-4-3=2 days