float datatye behave strange even with defined precision of 3

hi
i'm using floating point operations with the understanding of https://en.wikipedia.org/wiki/Floating-point_arithmetic and IEEE 754. i'm aware of precision problem, the 6 significant digits. i there for was testing the behavior of mariadb with less than five and last digit is a 0. hence all digits behind are defined.
please have a glimp @SimpleFloatTest.sql. on my implementation integers and anything with #.25 work fine. 0.025 or 0.23 or 0.24 fail to select.

the result is fancy. everything is stored correctly. if i extend precision the question rises if the last digit will be rounded or not (sprintf ("%e"). mariadb does rounding, perl does not, have to check compiler. but currently there is no precision question, if the result showed by SimpleFloatTest.sql appear on every installation.