Math Lesson 3 Adding Subtracting Money

okay today we're gonna look through some examples of problems that involve adding amounts of money together and subtracting amounts of money so for example if you were making purchase of something then you're gonna give the cashier certain amount of money they're gonna have to subtract how much you are spending and give you back the difference so we're gonna start with some simple examples and I'm gonna show you couple of different ways we can try these problems so this first one is not even on the worksheet but made this problem up using the prices that we see here so said you have one dollar you're gonna buy two tennis balls that cost 27 cents each so there are couple of things we have to do in order to solve this problems first of all we need to figure out how much we're spending all together so we need to find out how much not one but two tennis balls are gonna cost so I'm gonna do some addition for them so we're gonna when we do this there are couple of ways you can write it it might help you to just write out the money amount like this $0 decimal 2/7 and the same thing again cuz we're just adding the same number twice it might be helpful for you to put in your columns here just like we do when we're adding together any numbers so we've got of course our ones our tenth and our hundreds column always want to start on the far right side in our ones so we're gonna add 7 plus 7 which equals 14 so I'm gonna put the 4 from the ones place at the bottom the new 10 that we made moves over to the next column here we have 2 plus 1 for 3 and two more for 5 and over here we just have zero on zero so we're just gonna bring that down to the bottom and we want to make sure we put our decimal point in the same place all the way down and we'll put the dollar sign in there to be complete so we know that we're spending 54 cents altogether the next step is we need to subtract 54 cents from the one dollar that we we have so we know that we're spending 54 cents altogether we know that we start with one dollar so we're gonna put our one dollar that we have at the very top and this time we're going to subtract should have remembered to put an addition symbol there and we'll remember that we're subtracting over here one dollar and zero cents it's important to remember to mark those in there as well we're going to be subtracting this time 54 once again I'm gonna draw our columns so that we keep our numbers all together in the right place just like always we're gonna start at the far right now if start by looking here have zero take away four and I'm not able to do that because can't take bigger number away from smaller number so I'm gonna look over to the next column here my tens column there's nothing here for me to borrow so need to move over one more time to my hundreds column so I'm gonna borrow from here and if have one 100 and I'm borrowing one then left here have zero and I'm gonna bring that one over to here so now have ten here and now can borrow from here and come over to my last column so if I'm gonna borrow one from ten that's gonna disappear and I'm gonna be left with nine I'm gonna just sneak that down there and they know if I'm bringing one over from here I'm doing 10 take away for 10 take away 4 of course can display that quite easily there's my 10 get rid of 4 and I'm left with 1 2 3 4 5 and 6 in the next column you know the 0 and the 1 have been crossed out so I'm doing 9 take away 5 which is easy to do again you can hold up 9 here get rid of 5 of them left with 4 and if move over to the next column just have 0 take away 0 0 comes to the bottom the decimal place is there and have 46 cents left so that's gonna be the change left over now I'm gonna show you this same problem but instead I'm gonna work through it using actual money and show you how we'd figure that out ok so we're gonna work through the same problem again but this time instead of just writing out the numbers I'm gonna show you how we'd actually use real money or if you're using and money at home over the virtual manipulative hell we could break that down so know that have $1 know that two tennis balls cost 54 cents altogether so need to figure out if gave somebody this dollar how much I'd be getting back so need to get rid of 54 cents but of course this is one piece of money and can't do that so I'm gonna split it apart so the first thing know about dollar is that can also use 4 quarters to make that so I'm gonna do straight trade here 4 quarters so the amount of money hasn't changed now want to get rid of 54 cents so know that two quarters equals 50 cents so can get rid of 50 cents just like that and then only have to worry about 4 cents if want to show the numbers here can show now I've paid 50 cents so can say 4 take away 0 is 4 5 take away 5 is 0 0 take away zero is zero and still only have to pay 4 cents now once again can't make 4 cents out of 2 quarters so have to break one apart so I'm gonna take that quarter and then get out an equal amount of money using different coins 10 15 20 25 so the amount that's there hasn't changed but still can't make 4 cents out of that now you might not have pennies in your home anymore because they're becoming rare but if you don't then maybe you can just use something else to stand in as pennies so do happen to have some so I'm gonna take 5 pennies here 1 2 3 4 5 couple of American ones in there and take that it so there's still 50 Cent's here and now it's easy for me to get rid of 4 sentence just count them up 1 2 3 4 and what have left here is gonna be the change that get back so let's see if that gives us the same answer as we got before so I've got 25 35 40 45 46 cents left and can double check that by doing the 50 Cent's that had take away four more cents so can show that here 50 cents and still had to pay for so I'm trying to do zero takeaway for which can't do I'll go next door for 10 more the four stays and the one jumps over 10 take away 4 is 6 4 take away 0 is 4 0 take away zero is zero so that gives me the same answer as we got last time 46 cents okay for the last example we're gonna take one right from the worksheet I'm gonna do the second one right here and I'm gonna work through it using only numbers so this is if you're feeling confident with the money and you want to go ahead and try some of these more challenging problems so I'm gonna show you how to do this one noticed that they did the thing that warned you about in the first video where they write up cents amounts without using the dollar sign this is why don't like to do that because then you have over here 51 cents down here the dollar symbol showing dollar 15 so I'm actually going to change this to writing it up the same way so hello cat so back to business down here we have the football and in fact you'll notice they changed the way they wrote it anyway down here so we're gonna put zero cents or sorry zero dollars decimal 51 cents and for some reason Tina wants hockey stick to go with her football so we're gonna add dollar 15 down here for the hockey stick we're adding these together some 1 plus 5 gives us 6 5 plus 1 is the same thing in Reverse 0 plus 1 so the total cost is $1.00 66 so down at the bottom here we're gonna take what Tina has altogether dollar 75 and we're gonna subtract all together the cost of both of those items so dollar 66 and then we can go ahead and start doing the math so over here cannot do 5 take away 6 because can't take away larger number from smaller number so I'll borrow one from the 7 the 7 becomes 6 and over here now have 15 take away 6 if want to count that out can start at 15 hold up 6 and count them down so 15 sorry 14 13 12 11 10 9 so 15 take away 6 gives me 9 in the middle column have 6 take away 6 which is going to be 0 and over in the dollars there have 1 subtract 1 which is also going to be 0 so Tina's change after paying dollar 75 for items that cost dollar 66 is nine cents