Scientific American presents Math Dude by Quick & Dirty Tips. Scientific American and Quick & Dirty Tips are both Macmillan companies.

So far we've talked about the big ideas behind significant figures (things like where they come from, why they matter, and what they mean), and we've also talked about how to identify significant figures in a number. But we haven't yet talked about how to actually make calculations using significant figures.

In other words, we haven't actually talked about how to work with significant figures in the real world! So, how do real world significant figures work? That's exactly the question we'll be talking about today.

Calculations with Significant Figures
What do significant figures have to do with real world calculations? Everything! First of all, as we've talked about before, significant figures are one of the ways we can quantify the precision of real world measurements. Which means that every time we make a calculation about something we measure in the real world, we need to worry about significant figures.