Why is it said that if you fold a paper 42 times it will reach the moon?

Although this is of course not physically possible, mathematically, it is true.

The moon is 384.4 million meters from us on average.

The thickness of a piece of paper is 0.1 millimeters

So a paper’s thickness is 1E-4 meters thick and the distance from here to the moon is 3.844 E8 meters.

If you fold a paper this means it’s thickness will double each time so:

1 fold means 2*1E-4

2 folds means = 2*2*1E-4

etc.

until we reach 42:

2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*1E-4

This number passes the distance to the moon!