<p>If I'm dividing 2 numbers, 12442.23/2.2, then the answer must have only 2 significant figures. That's not possible right? So could you please explain that. </p>
<p>I also don't understand if I divide 1222/2, then it would mean 611, right, because they have infinite significant figures.</p>
<p>1) Only two sig figs.</p>
<p>2) Actually, sig fig-wise, you'd only end up with 600.</p>
<p>In the 2nd example, aren't they exact numbers? I'm confused.</p>
<p>When you divide or multiply, you round to the one that is least certain (less significant figures).</p>
<p>1) me.duh is correct- 2 sig figs</p>
<p>2) This answers depends on if the numbers in the operation are measurements or exact numbers. If the numbers are exact, which most of the time isn't the case, you don't need to worry about sig figs. Say for instance, and average of two measurements-in this case, sig figs wouldn't apply. However, if the (2) was an actual measurement, it is considered one sig fig and thus, you would only have one sig fig in the answer. If you have a TI-83+ that has Sci Tools, there should be a Sig Fig Calculator built into the application.</p>
<p>Hope that wasn't too confusing</p>
<p>huh? i didn't get that. Could you give an example.</p>
<p>So, how do you know something is an exact number or a measurement, if 23 could be a measurement?</p>
<p>I also don't understand if I divide 1222/2, then it would mean 611, right, because they have infinite significant figures.</p>
<p>2 is the one that defines how many sigfigs you need since it has the least. Since you only have 1 sigfig in 2, round 611 to 1 sigfig, or 600.</p>
<p>Ex 1: I have two measurements of liquid from a beaker. The first measurement is 253.5 mL and the second measurement is 255.6 mL. If I wanted to find the average of the two measurements I would, of course, divide the sum by 2. Sig Figs wise, the two is not considered a measurement, and thus is ignored in this situation. You would use 4 Figs in the final answer because the original measurements had 4 Figs.</p>
<p>Ex 2: If you have to divide two measurements, say 255.4 mL and 23.2 mL then you would end up with 3 Figs. The important thing to remember is, if you got the number from an instrument (beaker, graduated cylinder, scale, balance, etc.) It is not exact and should be dealt with in terms of sig figs.</p>
<p>2 is NOT the same as 2.00. You gotta think that using sig figs, 2 could be anywhere from 2.0-2.49. The measurement wasn't exact enough to make 2= 2.000 so that's why 1222/2 equals 600. The measurement wasn't exact enough to say that 1222/2 equals 611.</p>
<p>I'll answer your question about exact numbers. A measurement is hardly ever exact like in your first example. Exact numbers occur in cases when you know it has to be exact, no questions asked. For example, when you're calculating the mass of say 6 moles of an element. The six is exact. Or when you have a dozen eggs, the twelve is exact. In the second case you mentioned those numbers are probably exact because most measuring tools can measure decimal places accurately, but if they aren't then 600 would be a good answer.</p>
<p>And to answer your first question, it is possible to have two significant figures. You must use exponential notation. The answer would be 5.7 x 10^3. (The ^ carrot means "to the", is used for exponents).</p>
<p>So, would (2.00 * 10^2) be 1 or 3 sig figs?
The thing in parenthesis is what is in scientific notation.</p>
<p>This number is three sig figs</p>
<p>Then how many sig figs would be there if it was</p>
<p>2*10^2</p>
<p>Zeros in between numbers and after decimal points are always significant.</p>
<p>Two.</p>
<p>Isn't it only one? me.duh, I didn't understand your reply.</p>
<p>Uhh...I meant one. I typed two because of the number two. -_-;</p>
<p>Does that clarify my answer?</p>
<p>Just to be confusing: the density of water is 1.0 g/mL. No matter if you write down 1.0 or 1.0*10^20, the number is considered exact. You would record your answer by what ever else you're using. If you divided the volume of the acid by the density of water (say 22.5 mL/1.00 g/mL) you can just make the density of water as many significant figures as you need. Same goes for gas law constants and such...</p>
<p>^Are you sure about that? I was pretty sure that water's density was not exactly 1.0, but it was close to that so most people round up. It's more like .999, and that number is definitely not exact.</p>
<p>No, it is commonly assumed that the density of pure H20 is exactly 1.00000000000 g/mL. This is a constant from which many measurements base their derivative</p>