--description--

In programming, it is common to use assignments to modify the contents of a variable. Remember that everything to the right of the equals sign is evaluated first, so we can say:

myVar = myVar + 5;

to add 5 to myVar. Since this is such a common pattern, there are operators which do both a mathematical operation and assignment in one step.

One such operator is the += operator.

let myVar = 1;
myVar += 5;
console.log(myVar);

6 would be displayed in the console.

--instructions--

Convert the assignments for a, b, and c to use the += operator.

--hints--

a should equal 15.

assert(a === 15);

b should equal 26.

assert(b === 26);

c should equal 19.

assert(c === 19);

You should use the += operator for each variable.

assert(__helpers.removeJSComments(code).match(/\+=/g).length === 3);

You should not modify the code above the specified comment.

assert(
  /let a = 3;/.test(__helpers.removeJSComments(code)) &&
    /let b = 17;/.test(__helpers.removeJSComments(code)) &&
    /let c = 12;/.test(__helpers.removeJSComments(code))
);

--seed--

--seed-contents--

let a = 3;
let b = 17;
let c = 12;

// Only change code below this line
a = a + 12;
b = 9 + b;
c = c + 7;

--solutions--

let a = 3;
let b = 17;
let c = 12;

a += 12;
b += 9;
c += 7;