To calculate the standard deviation of those numbers: 1  1. 2  Work out the Mean (the simple average of the numbers). 3  2. Then for each number: subtract the Mean and square the result.4  3. Then work out the mean of those squared differences.5  4. Take the square root of that and we are done!o calculate the standard deviation of those numbers: 1  1. 2  Work out the Mean (the simple average of the numbers). 3  2. Then for each number: subtract the Mean and square the result.
FBF = Flashback Friday. #FBF is an acronym primarily used on Instagram, Facebook, Twitter, and Tumblr that stands for Flashback Friday. Users typically use the tag on photos of moments in their past, like last yearâs vacation or a childhood friend.
FBF, or Flashback Friday, is a popularly used hashtag on Instagram. When users use the hashtag #FBF, they usually tag in on a photo of something thatâs happened in their past, such as a vacation, party, or graduation ceremony. FBF posts usually only occur on Friday, but they can occur on other days for various reasons.