You should not have added the extra numbers, it should just be 12, 9, and 7. What you’ve written is a valid operation, but it is not what the test wants. The test say what they expect a,b,c to be assigned to so you should console.log(a,b,c), and see what their values are
Having the += sign means adding the left side to the right side. So what you’re having here is that you’re adding a + 3 + 12 which makes your a now equal to 3 + 3 + 12 whick is 18.
Instead of having redundant variables on the same line, your test expects you to simplify the operation by adding the value of the given variable to a certain number. Kindly look closely at the example :