lesson 2 homework module 4 grade 2

welcome to the homework for lesson 2 this is module 4 of great to get your name on here first we've got lot lot of problems to solve here but most of them are not it should go pretty quickly and I'm gonna rush through these because otherwise this video take half an hour and I'll just give couple of examples of different ways to to solve these if you want to do them on paper and it's we're it's all place value strategies and you can use scrap paper to show the air away or number bonds or just use mental math and write down the answer so I'll show you how to do it the air way and I'll show you how to do with number bonds and then I'm just gonna just go right through bunch of them so here's an idea of the the steps that you use mentally to solve it using place value strategies looking at the digits we're looking at 23 plus 30 actually we're working working on this right here right so two tens and three tens is five tens and that's 50 so if we're looking at 24 plus 30 we're looking at five tens and it's just for once because there's no other ones to add 54 and lot of these in this first section are gonna be just like that so in this one five tens plus four tens is nine tens and that's 90 and here's our five tens in our four tens and now we just have nine ones in one of the add-ons and no other wants to add to it so it's we're still gonna have the nine tens and but now we're gonna have the nine ones 99 so since there's some room to work with over here I'm gonna do this one first I'll show you the air away so if I'm gonna do this the airway would take to start with the 60 and add the 31st and that would get me to 90 and then I'll add the 8 once 98 and that's an example of the airway if I'm gonna add this using number bonds I'm gonna use this I'm gonna think of the 38 as 30 and 8 and that's gonna make 90 and then I'll have 90 plus 898 so there's an example of that's that's what it would look like if you used the air way to do it this is how you would look to use number bonds to do it if you're still if you're writing these out that's how you show it but I'm just gonna go through these and look at the digits and do it mentally so we've got 20 and 40 that's 60 with 8 more 68 18 and 30 that's 10 and that's third and that's 30 so that's 40 plus 8 more is 48 we already figured this 198 we did twice already we have 30 and 20 that's 50 and 5 more is 55 35 and 50 that's 30 and 50 that's 80 and 5 more is 85 15 and 20 that's 10 and 20 that's 30 and 5 more is 35 now 37 what do we need to add to it to get 47 we have all the ones we need we just need another 10 27 and 57 we just need tens we have two tens we need five so we need three more 30 17 and 87 we have all the ones we need already so we have to get from 110 to eight tens we need seven more tens and that's just 70 same thing similar thing here with 22 and 62 we have all the ones we need we have two ones for both for our sum and this atom so we just need to add we just need 10s for our other add end for more tens forty and twenty nine we need five more tends to get to 79 50 and here we have 11 191 so we have 110 we need nine tens we need eight more tens that's 80 now we're finding sums and we're using greater than less than or equal to two compare if you can't remember which one is which then think of the old reliable alligator eats the bigger number there's my little alligator alligators are hungry big number they're hungry so it's hungry alligator and it always wants to eat the bigger number all right so it's gonna face the open end of the mouth it's gonna face the larger number but we have to find every some first don't just write in greater than less than equal to as you go we have to write down what the sums are and write like which symbol works so 23 and 40 that's 63 20 and 33 it's 53 and 63 is greater 50 and 18 that's five tens so that's six tens and eight ones 48 and 22 more tens so that's 68 and those are equal 1960 well that's one more 10 and 9 1 so it's 79 and this is 3 more 10 so it's 69 and 79 is greater one more 10 for 64 is 74 and then now two more tensor 49 is 69 and seventy four is greater 21 and seven more tens is 91 and 18 and eight more tens is ninety eight ninety one is less than ninety eight thirty five and five more tens it's eighty five and twenty six and six more tenses 86 and eighty five is less than eighty six and we're using more place value strategies except now it's with subtraction right this first page is all edition using place value and airway or number bonds and now we're doing into it everything but now we're going to do it with subtraction six tens minus two tenths instincts six minus two it's four but we're talking about tens so four tens is forty and here we have it six tens minus three tens is three tens and we're not subtracting anyone so we still have the three ones 33 eight tens minus five tens is 3 tens it's eight minus five but since its tens that's thirty now we've got eight tens we're subtracting five tens three tens are left and we're still gonna get to keep all nine ones because we're not subtracting any ones that's thirty nine and so if we're gonna do this arrow way I'll give an example like did on the first page you could do this 110 at time and count down count backwards by tens but this is gonna be when you're subtracting tens it's little bit easier so 85 we're gonna subtract five tens 35 you just be able be writing it out air away number bond method would be thinking of this as an 80 and five this might be little more helpful then you can really see that the 80 minus 50 is 30 and you still have that 5 left 35 so there's the examples of how to do it and I'm just gonna go through these as fast as can here mentally we're only subtracting tens here so we have five tens that's 35 we still have those ones we're gonna keep those five ones seven minus three four tens is four tens when we still have those five ones 72 and 22 well we still have the two so we're subtracting zero ones but we need to figure out how many tens to take away from 78 from seven down to two that's five tens which is 50 and this is similar we can see we have the nine once we're not subtracting any ones so zero is our ones digit for our subtrahend and we have to get from four 10s down to 110 so we have to take away three tens 30 and same thing here we're not subtracting any ones so our ones digit will be zero in our for our subtrahend and then our tens digit is going to be eight we have to get down to two so we have to subtract six 10s 60 and here again we're not subtracting any ones so our ones digit and our subtrahend is zero and we have to get from six 10s down to four 10 so we have to take away two tends to do that it's 20 looking at this one we're not subtracting any ones again so zero ones in our subtrahend and we have to give them seven tens down to five tens that's two tens we have to take away and 99 I'm here again we're not taking away anyone's because we still have nine ones left after we subtract so our sub trend is gonna have zero for our ones digit and we have to get from nine tens down to six tens we have to take away 3 tens to do that complete each more than or less than statement 20 less than 58 that's 38 36 more than 40 so it's more than so we're adding these 7640 less then something is twenty eight forty that's so 28 is gonna be 40 less so whatever this is it has to be 40 more so is 28 less 40 lesson then it is okay to 40 40 less than 68 is 28 right 50 more than something is 64 50 more then so this is gonna have to be smaller number because this is more so this has to be less so it's got to be 14 50 more than 14 so that's right 50 more than 14 is 64 you can think of them that way it really helps for these kinds of puzzles these are these really are puzzles it's just more than less than if you say them out loud it makes big difference there were 68 plates in the sink at the end of the day there were 40 plates in the sink at the beginning of the day how many plates were added throughout the day use the airway to show you're simplifying strategy so I'm going to start this actually with tape diagram just to our this so read it and I'm gonna draw it 68 pleats at the end of the day so II for end sixty-eight plates and but in the beginning of the day there were beginning of the day there were forty and we need to know these are the plates that were added we don't know how many were added so whatever we had the beginning and then we added more and it ended up being the same as the 68 for the end of the day so we're trying to find the difference between 68 and forty so here's our arrow simplifying strategy right we have to do 68 minus 40 there's our number sentence and we're gonna use the arrow way to just count it back 16:10 to time 58 nice another 1048 nice another 1038 now that's one two three tens we need them to take away four tenths so it's one more 1028 twenty-eight more plates we're at it