6/2(1+2)=?

I came across a Facebook question, which simply test your arithmetic and mnemonic skills:

2 + 2 x 2 = ?

In an instant, the brain told me that the answer is 6 not 8. This is inline with the order of operations which is taught during your latter primary years in elementary.

Then, a more complex question came across which stirred up some nerds commenting on my wall.

6 / 2 ( 1 + 2 ) = ?

There are two possible answers on this question. The following shows my solutions assuming you arrived with the two possible answers:

If your answer is 1

  1. Compute the operation inside the parenthesis or brackets first, (1+2)
  2. Ergo, yours will be 6÷2(3).
  3. Multiply 2(3) because they are juxtaposed with each other.
  4. Ergo, yours will be 6÷6.
  5. Continue with the remaining operation.
  6. Ergo = 1.

But how could I end up with 9?

If your answer is 9

  1. Compute the operation inside the parenthesis or brackets first, (1+2)
  2. Ergo, yours will be 6÷2(3).
    • Other way of showing this is (6÷2)*(1+2)
  3. Then, do your computation from left to right following the order of operation of PEMDAS, (6÷2)(3).
  4. That makes your answer (3)(3) or 3 x 3.
  5. Ergo = 9.

This is also supported with logical computation when you do this on a scientific calculator or Microsoft Excel. Even Google supports this 😛

So both solutions follow the order of operations or PEMDAS and there’s no point of blaming your teacher for not teaching this stuff correctly.

It is debatable until today because the question itself is very unclear.

There goes your universal language.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s