What type would you choose for the following "numbers"?
A person's telephone number
string.
A person's height
float or double.
A person's age
int for performance or byte (0 to 255) for size.
A person's salary
decimal.
A book's ISBN
string.
A book's price
decimal.
A book's shipping weight
float or double.
A country's population
uint (0 to about 4 billion).
The number of stars in the Universe
ulong (0 to about 18 quadrillion) or System.Numerics.BigInteger (allows an arbitrarily large integer).
The number of employees in each of the small or medium businesses in the UK (up to about 50,000 employees per business)
Since there are hundreds of thousands of small or medium businesses, we need to take memory size as the determining factor so choose ushort because it only takes 2 bytes compared to an int, which takes 4 bytes.