Sunday Morning Math Puzzle

NPR ^ | January 29, 2012 | Ed Pegg JR & Will Shortz

[SMGFan]

Next Week's Challenge from listener Ed Pegg Jr.: Write the digits from 1 to 9 in a line. If you put a plus sign after the 2, a times sign after the 4, and plus signs after the 6 and 8, the line shows 12 + 34 x 56 + 78 + 9, which equals 2003. That's nine years off from our current year 2012.

? This example uses four arithmetic symbols. The object is to use just three of the following arithmetic operations: addition, subtraction, multiplication and division, in a line from 1 to 9 to get 2012 exactly. The operations should be performed in order from left to right. There are no tricks to this puzzle. Can you do it?

[SMGFan]

Someone might want to try this, but do not listen to NPR. I just listen for the puzzle :)

[Yo-Yo]

but do not listen to NPR. I just listen for the puzzle :)

Yeah, and you just read Playboy for the articles, right?

[trebb]

Yeah, and you just read Playboy for the articles, right?

Playboy has articles????

[martin_fierro]

Write the digits from 1 to 9 in a line. If you put a plus sign after the 2, a times sign after the 4, and plus signs after the 6 and 8, the line shows 12 + 34 x 56 + 78 + 9, which equals 2003. That's nine years off from our current year 2012.

Thanks. Electrifying stuff.

[ml/nj]

They virtually give you the answer.

12 + 34 x 56 + 78 + 9 = 2003
-78 +89 = +11
+7 -9 = -2

so
12 + 34 x 56 + 7 +89 = 2012

ML/NJ

[oh8eleven]

They virtually give you the answer.
Ah, but not if you read the question properly, grasshopper ... "The object is to use just three of the following arithmetic operations ...

[duckman]

You guys are reminding me why I had to drop Trig in high school.

[blueunicorn6]

Arithmetic on Sunday morning? Sadists.

[ml/nj]

Stupid puzzle!

ML/NJ

[KarlInOhio]

The operations should be performed in order from left to right. There are no tricks to this puzzle.

But 12 + 34 x 56 + 78 + 9 = 2003 requires that the multiplication be done before the addition operations. So which is it, left to right or multiplication first?

[aruanan]

But 12 + 34 x 56 + 78 + 9 = 2003 requires that the multiplication be done before the addition operations. So which is it, left to right or multiplication first?

Multiplication and division over addition and subtraction. A "puzzle" that depends on violating order of operations isn't really a puzzle.

[VietVet]

“...left to right or multiplication first.”

Multiplication, division, addition, subtraction, in that order, in the absence of parentheses.

[Daffynition]

[KarlInOhio]

Well, I went through all 390625 possible combinations of operators or their absence between the nine digits. Three came up with the right result (and two more had the "right" result, but only because the program I used rounded down fractional results) , but only one had three operators.

Highlight the following line to see the result.

1234-5-6+789=2012
The order of operations never came up because there is no multiplication.

End of answer.

[Tanniker Smith]

I missed the puzzle this morning. Thanks for posting it.

As for listening to NPR, I'll flip it on when everyone else is on break. Occasionally, I find a diamond in the rough, and they're doing something you might expect from them if you honestly didn't know that they're just a bastion of liberalism.

[aruanan]

But 12 + 34 x 56 + 78 + 9 = 2003 requires that the multiplication be done before the addition operations. So which is it, left to right or multiplication first?

I was responding to the above that showed operators.

[EasySt]

Nicely done.