A simple calculator. You just need to enter an expression to calculate the result. This design mode is more convenient to operate. For example: Enter "2*(3+6)+10/2.4", And click "Calculate" to get result. show result in console. Support expression error detection. For example: Enter "2*(3+6)+10/2.4+a12+100", and click "Calculate", will show error message in console. Expression error！ Position: 2*(3+6)+10/2.4+a12+100 --------------------------^ Error: Illegal character Support "+","-","x","/" and "(" operations.