1. Lesson 4

2.  Add and subtract multiples of 10 and some ones within 100.  Solve one- and two-step word problems within 100 using strategies based on place value.

3.  7 + ___ = 10  Let’s find missing parts to make ten. If I say 7, you would say 3.  Ready? 7.  Say the number sentence.  Let’s try some more numbers: 2327424858 4 3717 13

4.  When I say, 9+4, you say 10+3.  Ready? 9+4.  What’s the answer?  Let’s try some others: 19+4 8+5 48+3 18+3 8+3 29+6 19+6 9+6 49+4 29+4 67+4 17+4 7+4 27+6 17+6 7+6 88+5 18+5

5.  There are 5 yellow cubes. How many linking cubes am I showing in this stick?  How many in this stick?  What is the difference between 8 and 5?  What number sentence could I use to represent the difference between 8 and 5?  8–5=3.

6.  Has the difference changed?  But what new number sentence can I use to represent the difference between my two sticks?  9–6=3.  Is the difference still 3?  YES!

7.  I add more to each bar. Did the difference change?  Let’s test this idea. When we add the same amount to each number in a subtraction sentence, the difference stays the same.  Now let’s try this with a new problem. 34 – 28  Now that is challenging!  Try this one: 36 – 30.  How did you know the answer so fast?  Yes! Is it easier to subtract just tens!

8.  Now, can you tell me how 34 – 28 and my other problem, 36 – 30, are related? Turn and talk.  Now how long is each bar?  We added 2 to each bar to make the problem easy!  Now it’s your turn. On your white board, solve these problems by making a tape diagram. Add on to both numbers to make the problem easier. 22-8 22-8 26-19 26-19 33-18 33-18

9.  There are 6 red cubes on one end and 4 red on the other end. How many yellows are in the middle?  What is the total number of cubes?  Let’s make 2 different addition sentences. What is the addition sentence for the total number of cubes?  Now instead let’s join the 1 yellow with the 6 red.  How do you know this is true 6+5 = 7+4?

10.  Let’s use that same idea with larger numbers to make tens.  Let’s solve 28 + 36.  What does 28 need to be the next ten?  What is 2 less than 36?  How do you know this is true: 28+36=30+34?  We can also show 2 more for 28 with our number bond.  Let’s write both models in our journals and explain them to your partner.

11.  Let’s do some more practice with the following problems: 19+35 19+35 37+46 37+46 78+24 78+24 36+29 36+29

12.  Carlos bought 61 t-shirts. He gave 29 of them to his friends. How many t- shirts does Carlos have left?  Solve!  Share!

13.  I’m going to give you some number of ones. I want you to pull out as many tens as you can, and then tell me how many tens and ones. If there are no ones, only say the tens. Ready?  Say this number sentence. 10 ones = ____ ten. 20 ones = ____ tens. 63 ones. 75 ones.70 ones. 60 ones.23 ones. 97 ones.90 ones.79 ones.

14.  Let’s review some questions we should ask to solve a story problem: First ask, “Can you draw something?” Then think, “What can you draw?” Finally, “What conclusions can you make from your drawing?”

15. Directions: Solve a single-step word problem using a tape diagram and the Arrow way.  Don has 34 brownies. He bakes 22 more. How many brownies does he have now?

16. Directions: Solve a single- step word problem by drawing a tape diagram and using a number bond or the Arrow way to solve.  Sam has 46 red apples and some green apples. He has a total of 88 apples. How many green apples does he have?

17. Directions: Solve a two-step problem by drawing a tape diagram and using a number bond to solve.  There are 31 students on the red bus. There are 29 more students on the yellow bus than on the red bus. How many students are on the yellow bus?  How many students are on both buses combined?

18. Directions: Solve a two-step problem by drawing a tape diagram and using the Arrow way to solve.  Ms. Lopez cut 46 cm of yarn. Ms. Hamilton cut 22 cm fewer than Ms. Lopez. How many centimeters of yarn did Ms. Hamilton cut?  How many centimeters of yarn did they have altogether?