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Well I have the expression below can be evaluated in tow different ways according to my knowledge of order of operations:

$$\begin{matrix} 3+8\div2\left(10-2^3\right)-7 \end{matrix}$$

OK my try:

$$\begin{matrix} 3+8\div2\left(10-2^3\right)-7\\=3+8\div2\left(10-8\right)-7\\=3+8\div2\left(2\right)-7\\=3+4\left(2\right)-7\\=3+8-7\\=4 \end{matrix}$$

But when I put it in the calculator it's gave me $(-2)$, so the calculator doesn't divide $8$ by $2$ till multiply $2$ by $(10-8)$ just like this: $3+\dfrac{8}{2(10-2^3)}-7$.

I want to know which one $(-2)$ or $4$ is the correct answer for this expression? And why?

Willie Wong
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Mohammad Fakhrey
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  • Are you familiar with http://en.wikipedia.org/wiki/Order_of_operations? Some programs and calculators may be playing by a different set of rules. Wolfram Alpha gives 4. – Amzoti Oct 04 '13 at 06:05

1 Answers1

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at first you should use the PEDMAS rule.please check the calculation here. ie you must do 2*2=4 the divide 8]1

User8976
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