user: I'm working on some research for a new material and need to calculate a few things. First off, I have a sample with a mass of 300 grams and its volume is 50 cubic centimeters; I need to determine its density. Once that's done, I'm interested in the Fibonacci sequence up to the 5th number. Lastly, I'm curious about the greatest common divisor between the mass and volume of my sample. Can you crunch these numbers for me?

Available functions:
name: calculate_density
description: Calculates the density of an object.
parameters: type: dict
properties: mass: type: float
description: The mass of the object, in kilograms.
volume: type: float
description: The volume of the object, in cubic meters.
required: mass
volume
name: get_fibonacci_sequence
description: Calculates the n numbers of the Fibonacci.
parameters: type: dict
properties: n: type: integer
description: The number of Fibonacci numbers to calculate.
required: n
name: math_gcd
description: Calculates the greatest common divisor of two numbers.
parameters: type: dict
properties: a: type: integer
description: The first number. This should be the larger number.
b: type: integer
description: The second number.
required: a
b