A simple number puzzle is challenging people online with a deceptively easy question: Which number is missing? The image shows a grid containing numbers that appear to run in order from 1 to 60. At first glance, everything looks perfectly complete, but one number has been left out. Can you spot it without checking the answer?

The puzzle can be surprisingly difficult because our brains are naturally good at recognizing patterns. When we see a long sequence of numbers, we tend to scan quickly and assume everything is in the correct order. Instead of carefully checking every number, our eyes may move over the sequence while our brain automatically fills in what it expects to see.

To give yourself the best chance, slow down and examine the grid row by row. Start at the top and move from left to right, checking each number against the sequence. Try not to look at the entire grid at once, because the missing number can easily blend into the surrounding numbers. Take your time and resist the temptation to look at the answer.

If you’re having trouble, pay especially close attention to the lower portion of the grid and compare the numbers carefully. Claims that people over a certain age are unable to spot the missing number should be taken as part of the puzzle’s playful challenge, not as a scientific fact. Anyone can miss a number when scanning a crowded pattern.

So, did you find it quickly, or did you need several seconds to discover what was missing? The number that doesn’t appear in the sequence is 46. How long did it take you to spot it? Share your time in the comments and see whether your friends can find it faster!