Using Javascript number operators

Mathematical Number operators.

  • To create numeric expressions we are using mathematical operators which can be:
    Operator Example Comments
    +
    (addition)
    var sum1=50, sum2=30;
    var sum = sum1 + sum2;
    // sum will be 80 
    Used to add one operand with another operand.
    -
    (subtraction)
    var sum1=50, sum2=30;
    var sum = sum1 - sum2;
    // sum will be 20 
    Used to subtract one operand with another operand.
    *
    (multiplication)
    var price=10, quantity=5;
    var sum = price * quantity;
    // sum will be 50 
    Used to multiplicate one operand with another operand.
    /
    (division)
    var price=10, sum=5;
    var quantity = sum / price;
    // quantity will be 0.5 
    Used to devide one operand with another operand.
    %
    (modulo)
    var price=5, sum=11;
    var rest = sum % price;
    // rest will be 1
    Used to get remainder from one operand with another operand.
    -
    (unary)
    var sum2=11;
    var sum = -sum2;
    // sum will be -11
    Converts a positive value to an equivalently negative value, and vice versa.
    +
    (unary)
    var sum2=11;
    var sum = +sum2;
    // sum will be 11
    The operator does nothing; it simply evaluates to the value of its argument.
  • Expression can also be of incrementing and decrementing types:
     var count=10
     count++;              // Start with count and increment it. 
     count--;              // Start with count and decrement it. 
    // OR
     count = count + 1;    // Start with count and increment it with a value (1). 
     counter = count - 1;  // Start with count and decrement it with a value (1). 
    // OR
     count += 1;           // Start with count and increment it with a value (1).
     count -= 1;           // Start with count and decrement it with a value (1).
    The two first one has both two options which is prefix and postfix:
    var a = ++c;      // prefix operator - increments c and assign it to a
    var b = c++;      // postfix operator - assign c to b and then increment c
    var a = --c;      // prefix operator - decrements c and assign it to a
    var b = c--;      // postfix operator - assign c to b and then decrement c
    Program example using prefix and postfix with incrementing and decrementing:
    <script type="text/javascript">
      var value = 1;
      var result = value++ * 5;
      document.write("result: "+ result);
      document.write(" and value: "+  value);
      document.write("<br>");
      // prints: result: 5 and value: 2
      document.write("result: "+ --result);
      document.write(" and value: "+  value++);
      document.write("<br>");
      // prints: result: 4 and value: 2
      // but the result=4 and the value=3
      result = (++value * 5) ;
      document.write("result: "+ result);
      document.write(" and value: "+  value);
      document.write("<br>");
      // prints: result: 20 and value: 4
      document.write("result: "+ ++result);
      document.write(" and value: "+  --value);
      document.write("<br>");
      // prints: result: 21 and value: 3
    </script>
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