 Okay, ready? Okay, cool. So try this one. How many significant things are contained in each of the following? So if you'll notice A is 1,0.0, okay? So all of these zeros are significant, okay? Because the last zero of course is after the decimal point, so that's all the significant. So this one has three significant figures. B has a zero before the first non-zero integer, so that zero is not significant, okay? So it only has one, two, three significant figures. What's the reason? So this zero is before any non-zero integer. You always want to convert them to scientific notation. If you do that, then you'll be able to see how many significant figures are more easily. C is the same thing. This zero is not insignificant or non-significant because it's not before or it's not after a non-zero, even though, but this one here is significant, okay? This one, the n1 after the decimal. Okay, this zero, I guess they call it a captive zero, okay? It's always significant, okay? So we got 1, 2, 3, 4 here. Here we've got a captive zero and a zero at the end, but since it's after the decimal point, it's also significant. So we got 1, 2, 3, 4. And this one actually is the third question of the whole thing. This zero is significant, but this one's not, okay? Because it's the last zero before the decimal point without the decimal point there. Okay? So this one actually has three significant figures. And just to show you guys, right, if I were to put a decimal point afterwards, then we would have four significant figures.