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.