Learning significant figures can be difficult in science. But, there is a reason to learn them. Scientists and engineers use significant figures to show how accurate their measurements are and how accurate the instruments used to collect the measurements are.
Click the link to watch "Significant Figures and Significant Digits - The Rules" on YouTube:
The Rules of Significant Figures
Non-zero numbers are always significant
Any "trapped" zeros between two significant figures are significant
Any trailing zeros are significant only if there is a decimal in the number
Operation Rules for Significant Figures
When adding or subtracting: Answer is limited to the fewest number of significant figures after the decimal.
When multiplying or dividing: Answer limited to fewest number of significant figures in any number in the problem
Watch the video for examples of how to count, add, subtract, multiply and divide using significant figures.