The optical illusion can be quite tricky to solve the test as participants are required to fill it in a 15 seconds.
Not only do they put observation skills to the test, optical illusions could help determine intelligence too.
And with this brain teaser in front of you, solving it within 15 seconds might mean your eyesight is pretty good.
If you feel there isn’t a elusive number in the image, be sure you take a closer look.
Scroll down for the answer. Many people can’t find the number quickly but you can start by looking attentively at each row and column ever so quickly.
Then after a little of observing, you might just have your answer to the test staring just right at you.