# What's 0 - -2^2 on your Calculator ?

Discussion in 'Community Discussion' started by OSMac, Oct 14, 2013.

1. ### OSMac macrumors 65816

Joined:
Jun 14, 2010
#1
Try entering 0 - -2^2 on your calculator , most seem to give the wrong answer?

What's calc do you have , what's the result ?

2. ### wordoflife macrumors 604

Joined:
Jul 6, 2009
#2
4 on my Ti-84 Plus SE

But seriously, as strange as it sounds, your question is vague. Are you talking about 0 - (-2)^2 or 0 - -(2^2) or 0 (- -2)^2 , etc etc.

You need to know how your calculator works before you can use it. Depending on what the question is asking, I can get the 'right' answer.

3. ### Comeagain? macrumors 68020

Joined:
Feb 17, 2011
Location:
Spokane, WA
#3
The calculator is very strictly following order of operations as it knows them, whereas we are usually ignoring certain things. It's most likely giving you zero minus the opposite of 2 squared (4). Not zero minus negative two squared (-4).

4. ### OSMac thread starter macrumors 65816

Joined:
Jun 14, 2010
#4
Even simpler what is... -2^2

On a recent TI
[negative key ] [2] [squared] gives -4 .

On my old 80s Sharp el506
[2] [negative key] [squared] gives 4 as expected.

Sure know how to use your calc, but what's the reasoning of new calcs?
It seems the [negative] key does not enter a negative number,
Instead it multiples a by -1... Forcing the use of brackets.

5. Oct 15, 2013
Last edited: Oct 15, 2013

### OSMac thread starter macrumors 65816

Joined:
Jun 14, 2010
#5
[0] [minus] [2] [squared] makes sense to be -4

But

[0] [minus] [negative] [2] [squared] should also be -4

Just look at the last entry in the display below,
algebraic entry was suppose to improve things?

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6. ### Don't panic macrumors 603

Joined:
Jan 30, 2004
Location:
having a drink at Milliways
#6

if you want the negative to be included in the power operation, you have to include it in parentheses:

-2^2 = - (2^2) = -4
(-2)^2= +4

therefore
0 - -2^2 = 0 - -(2^2) = 0 - -4 = 0 + 4 = 4

7. ### OSMac thread starter macrumors 65816

Joined:
Jun 14, 2010
#7
The hp 50g is slightly better in algebraic mode,
If [minus] [negative] keys are pressed in sequence the operator displayed changes to plus so its clear you need to use brackets but it still allows negative 2 squared to display an answer of -4.

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8. ### Comeagain? macrumors 68020

Joined:
Feb 17, 2011
Location:
Spokane, WA
#8

That's what is going on as far as I can tell.