For some people, math comes naturally. For others, not so much. But this number riddle is stumping even the savviest mathematicians. The riddle was created by Adam Spencer, comedian, mathematician, and author of The Number Games.
In his riddle, Spencer wrote down the numbers 1 through 19 out of numerical order.
To solve it, you need to figure out the specific way he ordered the first 14 numbers and finish the riddle by adding the last five.
Here it is:
8, 18, 11, 15, 5, 4, 14, 9, 19, 1, 7, 17, 6, 16, ?, ?, ?, ?, ?
Here’s a hint: you don’t actually need to be a mathematician to solve this.
If you’re still stuck, here’s another hint.
Which five numbers are missing? 2, 3, 10, 12, and 13. We just need to figure out which order those should be in. It can’t be numerical since the rest of the riddle is out of order… so, what is it?
Ready for the answer?
As it turns out, all that’s required to solve the puzzle is the ability to spell.
Yes, Spencer ordered the numbers in alphabetical order as they’re spelled.
So, the missing last five numbers would be 10, 13, 3, 12, and 2 in that order.
Did you solve it under 60 seconds?
Up for more puzzle challenges? Try the one dubbed the ‘hardest ever’ by a university professor.