add[x,y] := x + y
multiply[x,y] := x * y
negate[x] := -x
invert[x] := 1/x  // Could also use inv[x] or recip[x]
conjugate[x] := Re[x] - Im[x] i

a = 3 + 2.5i
b = 7.3 - 10i
println["$a + $b = " + add[a,b]]
println["$a * $b = " + multiply[a,b]]
println["-$a = " + negate[a]]
println["1/$a = " + invert[a]]
println["conjugate[$a] = " + conjugate[a]]