Math riddles are one of the best ways to keep your brain sharp and test your logical thinking. Today, we’re breaking down a classic number puzzle that looks simple at first glance, but often trips people up if they rush through it.

Here is the riddle featured in the image:

“I’m a number. Double me. Subtract 10. You get 26. What number am I?”

If you guessed 18, congratulations! You got it right. But how do we reach that answer? Let’s walk through the exact steps so you can solve any puzzle like this in the future.

Method 1: Working Backwards (The Easy Way)

The fastest way to solve most sequence riddles is to reverse the process from the final result.

1. Start with the final number: We know the result is 26.
2. Reverse the subtraction: The riddle says “Subtract 10.” To undo this, we add 10 to 26:
   26 + 10 = 36
3. Reverse the multiplication: The riddle says “Double me.” To undo doubling, we divide by 2:
   36 / 2 = 18

And just like that, we arrive back at our starting number: 18.

Method 2: The Algebraic Approach (For Math Lovers)

If you prefer setting up equations, you can turn the riddle into a simple algebra problem.

Let x represent the unknown number.

1. “Double me”: 2x
2. “Subtract 10”: 2x – 10
3. “You get 26”: 2x – 10 = 26

Now, solve for x:

• 2x – 10 = 26
• 2x = 26 + 10
• 2x = 36
• x = 36 / 2
• x = 18

Let’s Double-Check Our Work

Before claiming victory, let’s test our answer against the original clue:

• Start with 18.
• Double it: 18 * 2 = 36.
• Subtract 10: 36 – 10 = 26.

The logic holds up perfectly!

Did you solve this in your head, or did you need a pen and paper? Share this post with a friend to test their brainpower!