The "modulo" operator, %
In many programming applications there is a common need for finding the remainder on division.
This is not available in al programming languages.
One can create an expression (or a function) to do this, x-int(x/y).
Most often used with just positive integers.
When using negative integers there is no consistent
understanding about the reult across different programming languages.
Example: We can fit 72 boxes into a crate, we have 857 boxes, how many will be
left over once we have packed them into crates?
Prime factors: not a huge use in real programming (unless you are writing programs for a math class) but expected knowledge
in computer courses (basically because it provided a great example of a "simple" concept that
has many points where the program to find prime factors can be improved).
The greatest common factor (greatest common divisor)
Essential for reducing fractions
Brute strength vs. consideration (prime factors) vs. elegance (Euclidean algorithm)
Not built-in to some programming languages
The least common multiple
Not a huge need in programming, but again, expected knowledge.
Another brute strength vs. consideration (prime factors) vs. elegance (product/gcf)
Factorial and the ! operator
Used in computing permutations and combinations
Not directly available in most computer languages
Expected knowledge because it is among the easiest examples of a "recursive" function
Fibonacci sequence
Probably will not come up in any real program you will write
Expected knowledge since it provides a great example for programming courses
Important as an instance where we assign few initial values and then produce
additional values based on the previously determined values.