Pasted

// Incrementing
var age = 20
 // the following lines all increment the value of age by 1
age = age + 1             
age += 1
age++
// there's also:
age = age - 2             
age -= 2
age++ // this only decrements by 1
  var this_value = 40
 // divides by 2
this_value /= 2
 // multiplies by 3
this_value *= 3