# Math expressions

I have the following piece of code part os a testing my knowledge… I am struggling a bit:

``````let kelvin = 293;
// convert the value of kelvin to celsius
let celsius = kelvin -= 273;
console.log(celsius);
// convert celsius to fahrenheit
let fahrenheit = (celsius * (9/5)) + 32;
console.log(fahrenheit);
// round number do whole number
fahrenheit = Math.floor();
console.log(`The temperature in \${fahrenheit} Fahrenheit.`);

``````

Not sure what could be wrong…

`.floor()` expects the number it is suppose round down/floor as argument

see documentation:

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/floor

In the questionaire says

``````Use the .floor() method from the built-in Math object to round down the Fahrenheit temperature. Save the result to the fahrenheit variable.
``````

If I comment the line:

``````fahrenheit = Math.floor();
``````

True, but `.floor()` doesn’t magically know which number it has to round down/floor. How is `.floor()` suppose to know?

As well as what @stetim94 said, when you assign a variable to the value stored in another, you don’t need to put `let var1 = var2 -= 4`, as you have here:

If you want to set `celsius` to `kelvin -273`, then you would do just that:

``````let celsius = kelvin - 273
``````

Notice how you don’t need the `-=`?

thank you all, after some research I found the right syntax for my code:

``````fahrenheit = Math.floor(fahrenheit);
``````

that worked fine. Thank you all