Computer Programming/Mathematical calculations
Most any programming language can use addition, subtraction, multiplication, and division between Computer programming/Variables to put the results into new Variables. Watch out for risk of Divide by Zero, which can give serious indigestion to some programming languages.
Many programming languages can calculate the number of days weeks months between two dates, provided the dates are defined using consistent Computer programming/Types.
Some programming languages can compute values using mathematics beyond simple arithmetic, such as Square Roots, Sine, Cosine, Logarithms, Imaginary Numbers.
If you want to know more you should read the sister article Ada Programming/Mathematical calculations which is a lot more elaborate.