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# Rational number word problem: checking account

CCSS Math: 7.EE.B.3

## Video transcript

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.