Let’s look at the sequence of digits: 1, 2, 3, 4, 5, 6…

Where had number seven hidden itself? At first glance in the given sequence there is no seven.

But when we look a bit closer again:

1, 2, 3, 4, 5, 6, 7…

…number seven can be easily seen.

How does it happen?
It’s only just a simple example of the illusory character of some mathematical data. It’s an arithmetic trick using human brain properties.