Calculator

(Ver 1.4 1/14/2013 by Meet Bhagdev and Ajan Jayant)
Type an expression in the following box (e.g., 10.5+20*3/25).

Here are some(but not limit to) reasonable test cases:
  1. A basic arithmetic operation: 3+4*5=23
  2. An expression with floating point or negative sign : -3.2+2*4-1/3 = 4.46666666667, 3+-2.1*2 = -1.2
  3. Some typos inside operation (e.g. alphabetic letter): Invalid input expression 2d4+1