It’s not uncommon for riddles to pop up on the web that spread like viral wildfire. The latest brainteaser sweeping the web is this math equation created by a man named Randall Jonas. Over 1.1 million people have been stumped by the math mystery he poses, which you can read below. Ready to give it a shot?

1 + 4 = 5

2 + 5 = 12

3 + 6 = 21

8 + 11 = ?

Confusing, right? Don’t feel too bad if this problem has you completely lost; according to Randall, only “one in a thousand” will be able to solve it, and the million-plus Internet users who have tried will agree with you that it’s a true head-scratcher. To spare you a major headache, The Telegraph broke down the solution in a handy little chart.

Those smart enough to come up with any answer at all suggested 40 or 96, and it turns out that either one is correct depending on how you approach the problem. To get the answer 40, the solution is to add the total of the first line to the numbers on the next line like this:

1 + 4 = 5

5 + 2 + 5 = 12

12 + 3 + 6 = 21

21 + 8 + 11 = 40.

For the final solution of 96, the process is a bit more complex and requires you to multiply the first number in each line by the second number, then add the product to the first number. Your solution would come out like this:

1 + (1 x 4) = 5

2 + ( 2 x 5) = 12

3 + (3 x 6) = 21

8 + (8 x 11) = 96

It’s an interesting problem that makes us wonder just how smart Randall Jonas must be to have come up with it in the first place. Although most of us may not be able to find the answer on our own, it’s certainly a fun puzzle that’s great to pass around the office and send to your family and friends.