There is no
float in FunC, and TVM in general. Floating point numbers are useful in scientific calculations. Because they don't have exact precision, they are usually not that useful in applications working with money.
TON amounts like 1.234567890 are stored as a big integer of nano tons like 1234567890 and when displayed to user, they are divided by 1 billion in client side applications, so the user can view a more friendly and understandable amount. Other monetary values like jettons use the same principle.
Because FunC gives you a very low level access to bits, someone can write a floating point library on top of it, but doesn't seem that useful.