How much do textbook solutions usually round?

[emyt]

this is just a small question, how much do textbook solutions usually round? I just did a question that came to an equation 4*10^6 - 1 * 10^4 / (0.01/0.5(4*10^6 - 1 * 10^4))
the calculator says like 796 000 500 000 000. something something and the textbook says that it should be 8.0 * 10^14.. well, it's close enough - but how can I ever know if it's just a rounding thing or my method was way off?

thanks

 

[tiny-tim]

Hi emyt!

(try using the X² tag just above the Reply box )

If it says 8.0, then it's rounding to 8.0 rather than 8.1 or 7.9 …

so it looks as if your 7.960005… is ok.

 

[tomcue]

for your question! It is common for textbook solutions to round to a certain number of significant figures or decimal places. This is usually specified in the textbook or by the instructor. In this case, it seems like the textbook is rounding to one significant figure, while the calculator is giving a more precise answer. It is important to pay attention to the level of precision required for a problem and to follow the appropriate rounding rules. If you are unsure, you can always ask your instructor for clarification. Additionally, checking your answer with multiple methods or using a more precise calculator can help confirm the accuracy of your solution.