This simple maths problem is making people lose their mind


A MATHS puzzle that was recently posted on Facebook has baffled thousands of

Within four days it racked up over 145,000 likes and was shared more than
46,000 times – and it seems people can’t agree on the answer.

At first glance the sums appear to be basic arithmetic – however, the
additions don’t add up.

The viewer is tasked with uncovering the total of the final sum – eight + 11 –
so the first step is to work out why the additions appear to be incorrect.

Have you found what makes the total of the other sums? Are you any closer to
finding a solution?

Once you have had a shot at figuring this out, scroll down to find out how to
answer the question.

Here are the methods that create the additions – but which one is correct?

The first method is that the total for one line runs on to the next, so the
total from the previous sum is added on to the next:

1+4 = 5

5+2+5 = 12

12+3+6 = 21

21+8+11 = ?

So if method one is correct then the missing number would be 40.

The second suggests that the numbers should be multiplied.

Therefore, in addition to multiplying the numbers you are presented with, the
second is multiplied by the first prior to the addition.

1 + (4×1) = 5

2 + (5×2) = 12

3 + (6×3) = 21

8 + (11×8) = ?

Again this works, so in this method the sum would look like this:

8 + (11×8) = ?

3 + 88 = ?

? = 96

In the original photo there is a difference of three between the numbers you
are adding and they increase by one every time.

Apart from when the series jumps from 3+6 to 8+11.


Looking again at method one, it appears that it is correct:









? = 96

So the missing answer actually assumes the answer found through method two,

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