# Math Help - Truncation vs Rounding

1. ## Truncation vs Rounding

I am trying to figure out applications in which I can use truncation and applications in which I could use rounding. I am working on this for a school project and I am having trouble identifying specific applications for each topic.

Any help or clues would be so greatly appreciated.

2. When a calculator makes a calculation and displays it on a screen, it can only display the numerical answer to a given length of decimal places (usually 8 or 9 for calculators), so it needs to round the final digit of a repeating decimal, in order to display the answer.

In computer programming, you may also need to make a calculation resulting in a decimal, but declare the result as an integer value, so a subroutine will round the decimal to an integer.

There's probably many more obvious applications but I can't actually think of too many. Maybe like measuring instruments are only accurate to a certain degree like $\pm 1\text{mm}$ for a ruler, could be another.

3. Originally Posted by missyd819
truncation
rounding.
Also, (1.00 x 10^2) is not the same as (1 x 10^2)

4. Originally Posted by missyd819
I am trying to figure out applications in which I can use truncation and applications in which I could use rounding. I am working on this for a school project and I am having trouble identifying specific applications for each topic.

Any help or clues would be so greatly appreciated.
If I understand you correctly you are looking for some examples where truncation or rounding is used. If so:

1. Truncation

Compare the actual size of a foot and the size of the adequate fitting(?) shoe. If the foot is a little bit larger than a specific shoe you can't round down.

2. Rounding

The currency in Denmark is crown which has 1 DEK = 100 øre. Prices are labeled exactly to one øre, BUT there are only coins of 25 øre or 50 øre.
An example:
You have bought 3 items which cost 14.99, 27.11 and 8.79. In total 50.89 but you have to pay 51.00 crowns.
If you had bought 3 items à 14.99, 27.11 and 8.75, in total 50.85 then you only pay 50.75 DEK.

5. Good examples earboth. I also thought of something to do with currency, but couldn't think of a suitable currency