What is 4×4+4×4+4-4×4 ?

July 23, 2013 — Leave a comment

Most respondents tend to answer this sequentially, rather than use PEMDAS* or BIDMAS** to ensure the mathematical operations are done in the correct order, that being:

  1. Parentheses or Brackets
  2. Exponents or Indices
  3. Multiplication
  4. Division
  5. Addition and Subtraction (not necessarily in that order – done sequentially left to right. PEMDAS sounds better than PEMDSA.)

So, 4 x 4 + 4 x 4 + 4 – 4 x 4

=      16   +   16  + 4  –  16       (do all the multiplications first)

=      20

The most common incorrect answer is 320. Can you work out how that might have been obtained?

* If you’re in the US or Canada            ** If you’re in the UK or Australia

No Comments

Be the first to start the conversation!

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