0

I'm using a TI-84+ and am trying to setup an equation that requires rounding up

I know how to round and round down with the TI-84 but I can't seem to figure out how to round up

Edit: the 'round down' function I mentioned isn't truly round down it's 'ipart' which gives you the integer portion of the number which for positive numbers does round down but for negative numbers rounds up which negates the suggestion of negate the number then round down then negate again

Improve this question
7
  • 2
    Thanks for your question, but this calculator is relatively recent (introduced 2004) and is still in production. Thus, it doesn't qualify as on-topic for this site. You might try Mathematics; they have a number of questions (albeit more sophisticated than this one) related to doing things on modern TI calculators.
    – cjs
    Commented Sep 17, 2019 at 4:10
  • @CurtJ.Sampson LOL I already asked over at Mathematics and I was told it was off topic for over there and was suggested here or stackoverflow
    – Goku Gohan
    Commented Sep 17, 2019 at 4:42
  • Ah! Sorry about misdirecting you, then. I'm not too familiar with Mathematics and, though I looked through their help pages, I didn't see anything mentioning calculators at all, so I just went by a quick search for TI-84 questions. (As you can see, it's good to check the help pages for what's on topic before posting in a new SE since redirects from others may be wrong.)
    – cjs
    Commented Sep 17, 2019 at 4:45
  • 1
    @CurtJ.Sampson Frankly I'm of the opinion that I asked in the right place the first time but it's such a niche issue that they don't really want to deal with it and are trying to pass the buck as it were but here's the link I was given meta.stackexchange.com/questions/324762/…
    – Goku Gohan
    Commented Sep 17, 2019 at 4:48
  • Ah, thanks for that link. I've pointed out to the person who suggested RC that the calculator is still being manufactured and supported, and is part of TI's current lineup. Given that he quoted our remit as, "How to use or preserve computing equipment that is no longer manufactured or supported by the manufacturer" in his answer, I can only think that he must have thought this was an obsolete calculator, not a current one.
    – cjs
    Commented Sep 17, 2019 at 5:14

2 Answers 2

Reset to default
6

Aside from the ipart function that you mention, there is also int which, according to the manual, returns the largest integer smaller equal to the input, i.e. it truly rounds down. You can use this to round up with the expression -int(-x).

Improve this answer
1

Add one and then round down. But make sure the number is not already an integer, because adding 1 and then rounding down would end up adding 1.

Improve this answer
2
  • indeed but the issue is I'm trying to stick this in the middle of a formula and I won't know if it's an integer or not ahead of time
    – Goku Gohan
    Commented Sep 17, 2019 at 4:41
  • I'm sure that calculator will have some way of doing conditional comparisons. I'm not familiar with that specific model so I can't suggest a specific procedure.
    – Greg Hewgill
    Commented Sep 17, 2019 at 4:59

Not the answer you're looking for? Browse other questions tagged .