What do you mean? It's exactly that in almost any programming language.
What is it you don't understand: "method" (a representation) or "decimal" (a number that consists of a whole and a fractional part)?
What is it you don't understand: "method" (a representation) or "decimal" (a number that consists of a whole and a fractional part)?
"Most decimal fractions cannot be represented exactly as binary fractions." - from the Python tutorial
The word "decimal" does not simply mean "a number that consists of a whole and a fractional part".
"Decimal" implies a ten based system, even though it's perfectly fine to say "binary decimal".
Using your own replacement words, it would be clearer to write "A floating point number is a representation of a number with a fractional part".
As a shorthand to explain what a float is to someone, "a decimal number" is an OK start though.
But sometimes that approximation breaks down even for simple examples, i.e. 0.1 cannot be represented as a float. This can be quite unexpected if your mental model is that "floats are decimal numbers with a certain precision".