How should you round with multiple nines after the decimal?

Question

I have the number 382.36840999. I want to round this number to the 6th decimal place. Would this be 382.368409 or 382.368410? Why?

Answer 1

So the rule for rounding numbers to some place (decimal or otherwise) if the value to the right of that place is 5 or above you should round up, and if it is below 5 you should round down. Let's use a simpler example to practice this idea. Suppose we have 109 and we wanted to round to the tens place, then we would add 1 to the tens place, giving 110. Let's do this again but now lets round to the ones place with 109.9. In this case we must add 1 to the ones place, but this gives us 10 in the ones place which gives 110! This is the essence of the rounding concept, you either add 1 (round up if >= 5) to the place you are rounding to or add 0 (round down if < 5) to the place you are rounding to. So in your problem you would use 382.368410 because you must round up/add 1 to the 6th decimal place, giving you 10 for that place (which is the same as adding 1 to the next higher place)

Hopefully this is clear. feel free to ask me further questions about this.

And remember, never stop learning!