Arithmetic Operations (32-bit floating point, 32-bit signed integer, 16-bit signed integer)

Question

Hi folks! What does "multiplying a series of number by a constant gain by using 32-bit floating point arithmetic operations (+,-,*,/)" mean? I have to multiply some numbers by 0.618 assuming the computer which will be perform the operation is restricted. The computer is capable of i)32-bit floating point arithmetic operations (+,-,*,/). ii)32-bit signed integer arithmetic operations (+,-,*,/). iii)Addition/subtraction and basic bitwise operations (aritmetic shift, inversion etc.) How can I perform such an opertion in C#? For example, how can I multiply 0.618 by -2046 by using the three capabilities mentioned independently from each other?