Rounding Off an Answer to Fit the Situation

Date: 09/12/2004 at 16:40:17
From: Yuna
Subject: Rounding

Can you describe one situation when you might purposely round up, and
another when you might purposely round down?

Date: 09/12/2004 at 16:54:14
From: Doctor Dotty
Subject: Re: Rounding

Hi Yuna,

Thanks for the question.

One question could be something like: "You have 40 square meters of 
wall to paint.  A tin of paint covers 15 square meters of wall.  How 
many tins of paint do you need to buy?"

Another question could be something like: "You have 8 tins of paint. 
You need 3 tins of paint to cover a wall.  How many complete walls 
could you paint?"

One of those questions needs the answer rounded down, and the other 
needs it rounded up.  Can you see which is which and why?

- Doctor Dotty, The Math Forum
  http://mathforum.org/dr.math/