Javascript - Cannot Add 2 Numbers Correctly

I am simulating a calculator using Javascript. Where a user can input 2 numbers in a given text box, and it will display sum, product, difference and division. Here is my function

Solution 1:

Because + is also a String Concatinater in JavaScript. use parseInt(var1) + parseInt(var2) it will work. also have a look on ---> Javascript Operators

to understand the + operator. Thanks

Solution 2:

If you're taking in the numbers in a text box they're treated as strings, so the + operator will do string concatenation. The * operator doesn't mean anything in relation to strings, so the javascript engine will try to interpret the inputs as numbers.

You can use parseInt on the inputs to convert them to numbers, or use the html number input type.

Solution 3:

try

console.log("Sum = " + (parseInt(num1) + parseInt(num2)));

or

console.log("Sum = " + (0 + num1 + num2));

also make sure you are calling the function like

calculate(4, 3);

and not

calculate('4', '3');

Solution 4:

At least one of your inputs to calculate() is string. + is defined for string so become 43. While */- are not defined for string and Javascript "cleverly" convert them to int.