There are a number of functions which perform arithmetic operations on numbers, they take a varying number of values as their arguments returning a new number as their result. When given only exact arguments, an exact result will be returned.
This functions adds its arguments then returns their sum.
If this function is just given one argument (number1) that number is negated and returned. Otherwise each of numbers is subtracted from a running total starting with the value of number1.
(- 20) ⇒ -20 (- 20 10 5) ⇒ 5
This function multiplies its arguments then returns the result.
This function performs division, a running-total (initialised from number1 is successively divided by each of numbers then the result is returned.
(/ 100 2) ⇒ 50 (/ 200 2 5) ⇒ 20 (/ 3 2) ⇒ 3/2 (/ 3.0 2) ⇒ 1.5
This function returns the result of adding one to number.
(1+ 42) ⇒ 43
Returns number minus one.