Rational number word problem: checking account

At the beginning of the week, Stewart's checking account had a balance of negative $15.08. On Monday morning, he deposited a check for $426.90. On Tuesday morning, he deposited another check for $100. How much was in Stewart's checking account after the second deposit, so after both of these deposits right over here. So he starts off with a negative balance. So a negative balance means that he's overdrawn his checking account. He actually owes the bank money now. Luckily, he's now going to put some money in his bank account. So he'll actually have a positive balance in his checking account. So he's starts off with the negative $15.08. And then to that, he adds $426.90. And then he adds another $100. So he started off with negative $15.08. And then to that, he adds $426.90 and $100. So that's $526.90. And so how much is going to have in his bank account? He started owing $15.08, and then he's going to add $526.90. So one way to visualize it is, if you think about it on a number line, if this is 0 right over here, he's going to start off at negative $15.08. But then he's going to add $526. So this right over here, this is $15.08 to the left. That's how much he owes. And to that, he's going to add $526. So I'm not drawing this to scale. But to that, he is going to add $526.90. So the amount that he's going to be in the positive is going to be $526.90 minus the $15.08. It's essentially going to be this length right over here. That's how much he's going to be in the positive. And that's going to be $526.90 minus $15.08. So that's going to be, and we can even just rewrite this so it actually looks exactly like that. That's exactly the same thing as $526.90 minus-- adding a negative is the same thing as subtracting a positive-- minus $15.08. And this is-- I will do this in another color-- $526.90 minus $15.08. Let's see, 0 is less than 8. Let's make that a 10 and borrow from this 9. So that becomes an 8, or I guess you could say we're regrouping. Now, everything up here is larger than everything there. So 10 minus 8 is 2. 8 minus 0 is 8. We have our decimal. 6 minus 5 is 1. 2 minus 1 is 1. And then you have 5 minus nothing. So he is left with $511.82 after his second deposit.