The number column type is designed to hold numbers. It is a general purpose column type for numerical values. You can use it for various purposes like count of items in stock, with different units like kilograms, kilometer, day, month, year, mile, celsius, etc. When you create a new Number column, you can choose the minimum and maximum value and the number format.
Multiple number formats are supported
You can choose Integer, Number with decimal, Percent, Rounded Percent, Scientific, Engineering, Accounting, Unit format, Currency and Rounded Currency formats.
Note: if a cell in a percent column contains a number displayed as 80% and then you change the column type to number, then after conversion, the cell value will appear as 0.8, because the underlying value in the cell is 80/100, i.e., 0.8.
If you choose the unit number format, you can then choose the type of unit like 'Kilometer', 'Acre', 'Degree', etc.
If you are looking to store an amount of money, try the currency column type. It allows you to choose from a list of currencies