<p>I'm studying for my AP Chemistry class, and I'm having difficulty with significant figures.. not with simple equations and being able to tell how many significant figures are in a number, but with more complex problems.</p>
<p>for example,</p>
<p>6.071 x 10^(-5) - 8.2 x 10^(-6) - 0.521 x 10^(-4)</p>
<p>The answer is 4 x 10^(-7) according to the book.</p>
<p>When I just plug in the equation into a calculator, i get the answer, except with decimals after the 4.</p>
<p>I don't understand how the order of operations work with significant figures problems, and in this case, with both multiplication and subtraction, how to limit the number of significant figures in the answer. </p>
<p>can anyone explain this step by step? it'll be very much appreciated (;</p>
<p>Honestly, don’t worry about it. Just put three sig figs for everything. On the grading scale, they allow ± one digit of significant figure error. And its not very common that they have answers that are one digit or five.</p>
<p>Ok, well when you subtract numbers, your answer has to have the same number of significant figures as the subtrahend w/ the least number of significant figures. Here, all three are in scientific notation, so: 6.071 x 10^-5 has 4, 8.2 x 10^-6 has 2 and .521 x 10^-4 has 3 (just count the number of significant figures in the decimal part i.e. before the 10^n) Therefore, the least number is 2, and you answer should have two</p>
<p>I don’t know why your book has only 1 o_0</p>
<p>yeah, that’s what I thought too… well, thank you anyway! I guess this was sorta a random topic to put on here :)</p>