Math Problem: Exponent

[valkener]

I'm a bit embarrassed but I found this question in Manhatten and it looked odd to me:

-5^2 = ?

Answer is: -25

I thought it would be 25 because but I guess (-5)^2 = 25 does not equal -5^2???

[alf10087]

Order of operations question. Remember PEMDAS.

After Parenthesis (of which there are none) you have to apply Exponents: 5^2 and THEN apply the -, which can be seen as a -1 Multiplying the 5.

Edited October 30, 2012 by alf10087

[pemdas]

some one called me , there's difference between (-5)^2 and -5^2. As Alf correctly explained unless the parentheses are present we follow the arithmetical operations' order (parentheses, exponents, multiplication, division, addition, subtraction) from the left to the right usually reminder for those whose regular alphabetical reading habit is from the right to the left (e.g. Hebrew, Arabic)

[ktel]

BEDMAS is how I learned it (Brackets, Exponent, Division/Multiplication, Addition/Subtraction). Weird Americans

[pemdas]

who's one? I am not American

[alf10087]

I'm not American either.

PEMDAS or BEMDAS: basically the same.

[TakeruK]

I thought it was weird that the poster mentioned PEDMAS instead of BEDMAS too. But then Wikipedia told me:

"In the United States the acronym PEMDAS is common. ... Canada uses BEDMAS and the UK uses BIDMAS or BODMAS. In Canada and other English speaking countries, Parentheses may be called Brackets, or symbols of inclusion and Exponentiation may be called either Indices, Powers or Orders, which have the same precedence as Roots or Radicals. Since multiplication and division are of equal precedence, M and D are often interchanged, leading to such acronyms as BODMAS.

...

PEMA is one of the mnemonics taught in New Zealand. This makes the equivalence of multiplication and division and of addition and subtraction clear."

Interesting!