It is resulting as string . Like 4+2=42 . How to make it 4+2=6.

Question

when I changed the code to ask for input, instead of returning 42 it'd return 402.
(or instead of 1+1=2 it'd return 1+1=11)

var a = prompt();
var b = prompt();

function addNumbers(a, b) {
var c = a+b;
return c;
}
document.write( addNumbers(a, b) );

Answer 1

var c = Number(a)+Number(b);

Answer 2

Additionally, Number() returns NaN (Not a Number) when either <a> or <b> as its argument were not convertible to a number.

It might worth to consider checking that neither Number( a ) nor Number( b ) was NaN, before adding the two.

a = Number( a );
b = Number( b );
if( !isNaN( a ) && !isNaN( b ) )
{
return a + b;
}
return 0;

Answer 3

makhrab dip

When you takes user input it returns as a string so 4 and 2 are string.

try this:

var a = prompt();

console.log(typeof a)

so either you can write Number(prompt()) or you can write parseInt(prompt(), 10)

var a = parseInt(prompt(), 10);
var b = parseInt(prompt(), 10);

console.log(a + b);

Answer 4

You can also convert to a number by using the following...

var c = parseInt(a) + parseInt (b);

Answer 5

var a = prompt();
var b = prompt();
var c = +a + +b;
document.write(c);
If you prepend var a and b with + sign this will work also.

Answer 6

By default the input are string. So they are just concatenated when added. Convert them to numbers to add.

return Number(a) + Number(b)

Answer 7

Use TryParse to check for int then add.

Answer 8

Var c = prompt(a+b)