Mental Floss

Brain Game: The Elevens Puzzle


First, examine the equation below.

the 11 puzzle
the 11 puzzle /

Obviously, this equation is false. There are a few ways we could alter the equation to make it true, such as removing the + from the left side and the × from the right side to make both sides read 1111. This maneuver would NOT solve today's Brain Game, however. Too easy. Your goal:

Find a way to insert the SAME SINGLE MARK to the SAME SPOT on both sides of the equation in order to make it true.

Here is one ANSWER.


Adding a decimal point between the first two digits on each side of the equation would make it read:  1.1 + 11 = 1.1 × 11, which would be true since both sides would equal 12.1

Did you come up with a different answer? Please scoll down and post it in the comments; we're garnering a fun Brain Game fan base and would love to hear from you. Thanks!