Grade 3 Math Question

[The_Grudge]

I'm embarassed that I have to ask this, but here goes...

I have a report that displays a summary of totals in two columns.
One of the columns is this years YTD total, and the other column is last years YTD total.

For example, this year there were 714 people, last year there were 901 people. That means the percent decrease was -20.75% correct? Okay.

So what do you do when last years total was zero. Let's say for example last year was 0, and this year it's 14. What should I display in the "% Diff" column for that!! Excel gives me a #DIV/0 as it should, but there has to be a percent difference doesn't there, because there IS a difference!!

[The_Grudge]

It's INFINITY.

[bushmobile]

depends which way you look at it - if you think of the difference as a percentage of 14 then it's a 100

if you think of it as a percentage of 0 then it just doesn't exist (it's not infinity in it's traditional sense)

[capsulecorpjx]

It's INFINITY.

Not even infinity. Because 0 * Infinity = 0

I'd say just an increase of 14

[BramVandenbon]

infinity*0 = undefined.

(Pretty logic if you think about it...
a number multiplied with 0 is 0.
a number multiplied with infinity is infinity.)

undefined could be any number or no number at all.

In short:
x/0 = infinity, some school books will say "no answer" because they don't want to go in trouble explaining that 0*infinity=x. Which could be true since x is undefined as I mentioned above.
0/0 = undefined, some school books will say "any number"

[autoactuary]

This is such a simple question and got way off track with the infinity thing. When you last YTD = 0 and the current YTD <> 0 then you simple define it as N/A. It is impossible to measure the change of something from a period when it didn't exist to a period where it did exist because you can't measure the change in something that doesn't exist. Therefore it is not infinity or any finite measurement it is simply N/A.