Significant Figures/Significant Digits: in Measurement, in Numbers, in Calculations; sig fig rules 

This video goes through an explanation of significant figure rules: 0:47 How significant figures are derived in measurement, 3:18 How to determine significant figures in a number, and 8:42 Applying significant figure rules to a calculation. Also included is how to change numbers to scientific notation to clarify sig figs 5:15 in numbers with leading zeros around a decimal, and 6:39 in numbers with trailing zeros without a decimal.