Before we start, we need to know the rules to adding integers. If the numbers you are adding together have the same sign (positive or negative), you add the absolute value of each number and use their sign. If their signs differ, you subtract the numbers and use the sign of the number with the the largest absolute value.
With that information, who can solve the equation on the board?
x = 300 since you subtract the two numbers' absolute value and use the bigger one's sign to find the answer.
That's correct, Zoe! Who has answer for this next equation?