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A Seemingly Simple Math Problem

What is the answer to this problem?

1 + 1 + 1 + 1 + 1
1 + 1 + 1 + 1 + 1
1 + 1 × 0 + 1 = ?

30.

There are two tricks to this one. The first is 1 × 0. But it’s mostly there as a distraction. Yes, 1 × 0 is 0, but that doesn’t affect anything else in the equation. The second, far trickier element is that the lines ending with 1 don’t have a + sign next to them. That means they should be combined with the following line.

Let’s put the equation all on one line, shall we?

1 + 1 + 1 + 1 + 11 + 1 + 1 + 1 + 11 + 1 × 0 + 1 = ?

And the answer to that equation is 30.


Posted in Brain Teasers

 

11 Comments on "A Seemingly Simple Math Problem"


Allison (mathematician) says
April 1, 2015 @ 22:45

Really were you people educated?

Okay here is a math lesson.

So the equation is…

1 + 1 + 1 + 1 + 11 + 1 + 1 + 1 + 11 + 1 x 0 + 1 =

So let’s start with the bigger numbers. 11 + 11 = 22
Then plus 9
22 + 9 = 31
31 x 0 = 0

Come on!!!!!!!
ANYTHING times 0 is ALWAYS 0
If you did a trillion times 0 it would still be 0!!!!


Dan says
April 2, 2015 @ 15:22

@Allison What about the order of operations? Multiplication before addition.


Ciel Takuro Yuki says
July 8, 2015 @ 10:05

nice one, classy


Ben (Not a mathematician) says
February 18, 2016 @ 05:51

My Ans=1
1+1+1+1+11+1+1+1+11+1 x 0+1
= 30 x 0 +1 = 1

For the 1×0 to effect the equation differently surely it needs to be in brackets e.g.
1+1+1+1+11+1+1+1+11+(1×0)+1
= 29+0+1=30
1+1+1+1+11+1+1+1+11+1x (0+1)
=30×1= 30

I may have missed a step but surely unless you alter the position of the “x 0” to the end of the equation then the answer can’t be 0 can it? I was educated in the UK a long time ago so perhaps that’s a problem ;>) GCHQ will know!


Jayasmita says
June 7, 2016 @ 08:47

1 + 1 + 1 + 1 + 11 + 1 + 1 + 1 + 11 + 1 x 0 + 1 =?

while evaluating mathematical expressions, the order of evaluation of mathematical operators is important else we will not get the correct result. And the order of operation is PEMDAS that is (Parenthesis, Exponents, Multiplication, Division, Addition, Subtraction). According to this rule, multiplication should happen first in the given mathematical expression. So the result is:

1 + 1 + 1 + 1 + 11 + 1 + 1 + 1 + 11 + 0 + 1 = 30


vignesh says
June 29, 2016 @ 12:46

Excellent keep it up!!!☺☺☺


Joe says
July 22, 2016 @ 13:45

The answer is 2. Let’s break it down.

Line 1: “1 + 1 + 1 + 1 + 1”
There is no equals here, there are no operators, and you cannot span a number across multiple lines without a hypen, which means it is not part of an equation. It is simply a bunch of numbers and operators and stands alone as an incomplete thought.

Line 2: “1 + 1 + 1 + 1 + 1”
See above for Line 1.

Line 3: “1 + 1 × 0 + 1 = ?”
Ah, now we have an equation. 1 + 1 X 0 +1, using order of operations, yields 1 + 0 + 1, or 2.

Allison and Ben, you guys need to go back to 6th grade math and learn order of operations.


Joe says
July 22, 2016 @ 14:05

The answer is 2. The first 2 lines are fragments.


John A says
September 7, 2016 @ 16:53

I like how some people are actually arguing about the answer. The answer is 30. Doesn’t matter how many times you say otherwise, 1 + 1 + 1 + 1 + 11 + 1 + 1 + 1 + 11 + 1 × 0 + 1 = 30. Period. End of story. #itscalledmath


JERRY says
December 9, 2017 @ 08:01

EACH LINE IS SEPERATE PROBLEM, SO LAST LINE ANSWER IS 2. MERRY CHRISTMAS.


Oliver S. Daniel says
November 6, 2018 @ 13:24

As Joe and also Jerry say, the answer is 2. There is no indication whatsoever that the lines should be combined together. The first two lines are in no way connected to the last line.


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