Why is 0,25 - 0,125 = 0,125????!

It just does not make sense..

And it said I had to convert it too

1/4 (0,25) - 1/8 (0,125) = 0,125?

0.25 = 1/4

0.125 = 1/8

and 1/4 - 1/8 = 1/8 = 0.125 <<<<<<<<<<

its a key rule while doing mathametical calculations that the 0 after the decimal (.} is not counted if its to the right.
so as per this key rule: 0.125 + 0.125 = 0.250
but since the 0 on the other side of the decimal (.} shall not be counted: 0.125+0.125=0.25