Wolfram: Arithmetic Basics
Addition
(* short syntax *) 3+2 (* FullForm syntax *) Plus[3, 2]
Substraction
3-2 (* FullForm syntax *) Plus[3,-2]
Multiplication
3 * 2 (* FullForm syntax *) Times[3, 2]
Multiplication can also be done with a space between numbers.
3 2 (* 6 *)
Division
3/2. (* 1.5 *) (* FullForm syntax *) Times[3, Power[2., -1]] (* 1.5 *) (* 3/2 return as is. when integer is divided by another integer, result is an exact fraction. *) 3/2 (* 3/2 *) (* to get approximate number, wrap it with N[] *) N[3/2] (* 1.5 *)
Power
3^2 (* 9 *) (* FullForm syntax *) Power[3, 2]
Remainder, modular arithmetic
(* remainder, or modular arithmetic *) Mod[11, 3] (* 2 *)
Celing, Floor, to Integer
Ceiling[4.2] (* 5 *) Floor[4.2] (* 4 *) (* HHHH------------------------------ *) Round[4.5] (* 4 *) IntegerPart[4.2] (* 4 *)
Replace by Zero
Chop[0.0000000000001] (* 0 *) Chop[0.00002] 0.00002 (* replace by 0 if smaller than 0.01 *) Chop[0.00002, 0.01] (* 0 *)
Testing even/odd
EvenQ[4] (* True *) OddQ[3] (* True *)