Math problem leaves the internet scratching their heads

If you’re like me, you’re probably grateful that the days of confusing math problems and endless algebraic equations are long behind you, back in high school. I mean, who wouldn’t want to avoid sitting in a stuffy classroom, surrounded by loud, misbehaving students, trying to figure out how to solve a tricky equation?

That said, I do know there are some people out there who actually enjoy math, who get a thrill from solving problems that would leave the rest of us scratching our heads. For those of us who are more creative than logical, math often feels like a giant puzzle we don’t want to solve.

But even for people like me, there’s something oddly satisfying about solving a good puzzle or riddle online. I don’t rush through them—it’s all on my own time—but when I finally crack the code, it’s a small victory.

And here’s the best part: I’m definitely not alone in this. There’s a whole community of people who love to challenge their brains with math puzzles and patterns, and I’ve found myself diving into that world more often.

It’s exciting! So, to put your brain to the test, we’ve got a fun (and tricky) puzzle for you today. Are you ready? Let’s dive in!

Here’s the puzzle:

If 1+4=5, 2+5=12, and 3+6=21, what’s 5+8?

Maybe it’s easier to understand if you see it written out like this:

• 1+4 = 5
• 2+5 = 12
• 3+6 = 21
• 5+8 = ?

This math puzzle has stumped a lot of people, and I’ve seen countless debates online about what the right answer could be. The key to solving it depends on the approach you take and the method you use to crack the code.

And guess what? There’s not just one answer! There are actually several, and each one uses a different way of thinking about the problem.

So, if you’ve been trying to figure it out and want to see if you’re on the right track—or if you’re like me and need the solution after getting completely frustrated—check out these five different ways to solve it. You might be surprised by the results!

Solution 1:

• 1 + 4 = 5
• 2 + 5 = 2 + 2(5) = 12
• 3 + 6 = 3 + 3(6) = 21
• 5 + 8 = 5 + 5(8) = 45

Algorithm: A + A(B) = C
Answer: 45

Solution 2:

• 1 + 4 = 1 + 4 + (0) = 5
• 2 + 5 = 2 + 5 + (5) = 12
• 3 + 6 = 3 + 6 + (12) = 21
• 5 + 8 = 5 + 8 + (21) = 34

Algorithm: A + B + C’ = C, where C’ is the previous answer
Answer: 34

Solution 3:

• 1 + 4 = 5 = 5
• 2 + 5 = (5 + 2) + (5) = 12
• 3 + 6 = (7 + 2) + (12) = 21
• 5 + 8 = (9 + 2) + (21) = 32

Algorithm: For {X=5, C = X + C’, X = X+2}; where C’ is the previous answer. A and B aren’t used in the equation.
Answer: 32

Solution 4:

• 1 + 4 = 5
• 2 + 5 = 7 (in base 5) = 12
• 3 + 6 = 9 (in base 4) = 21
• 5 + 8 = 13 (in base 3) = 111

Algorithm: For {X=6, C = (A + B)^(10 -> X), X -1}
Answer: 111

Solution 5:

• 1 + 4 = 5
• 2 + 5 = 7 (in base 5) = 12
• 3 + 6 = 9 (in base 4) = 21
• 4 + 7 = 11 (in base 3) = 102
• 5 + 8 = 13 (in base 2, aka binary) = 1101

Algorithm: For {X=6, C = (A + B)^(10 -> X), X -1}
Answer: 1101

As you can see, there’s more than one way to crack this code, and all of these solutions are valid depending on how you interpret the numbers.

It’s all about the method you use. Some people get really into these puzzles, loving the challenge of figuring out the pattern, while others might prefer a more straightforward approach.

What do you think of this puzzle? Did you figure it out on your own, or did you get stuck somewhere along the way? Let us know in the comments below!