1. Addition & Subtraction
4.NSBT.4 Fluently add and subtract multi- digit whole numbers using strategies to include a standard algorithm.

2. What do I have to do?
4.NSBT.4 Fluently add and subtract multi-digit whole numbers using strategies to include a standard algorithm.
Add whole numbers with 1, 2, 3, 4, 5, or 6 digits
Subtract whole numbers with 1, 2, 3, 4, 5, or 6 digits
Illustrate and explain how you got your answer
Borrow and Regroup as needed

3. 4-3 Adding - Review Make numbers bigger by combining values
Whole numbers are not fractions, decimals, or parts
Regrouping happens when a total at a place value is greater than 9 – also known as carrying
I DO – MODEL:
12, =

4. WE DO - Try this!
Add the following numbers. Does it matter how you write them? Can you estimate what the answer will be? = =
1, =
8, =
12, ,581 =
548, ,984 =

5. WE DO - Try this! ANSWERS
Did it matter how you wrote them? Did you estimate the answer? Were you close?
= 27
= 445
1, =1,252
8, = 8,576
12, ,581 = 17,426
548, ,984 = 572,348

6. YOU DO - Practice on your own
Open your MATH WORKBOOK to Reteaching 4-3 and complete all of the problems.
If you finish early, complete Practice 4-3 as well.
ALTERNATIVE: Pages ALL ODD problems 1-31.
TURN THIS IN BY THE END OF THE PERIOD

8. Reflect and Review
In your math journal, write 3 sentences about how to add and when to add. Can you think of times in your everyday life that you add?
MATH NOTES (Copy to your Math Journal)
We add when we see words like: sum, all together, in all, total, and plus
We add when we have unequal groups and need a total
When we have more than 9 in any place value, we write the ones digit in the sum and “carry” the tens digit

9. Addition & Subtraction
4.NSBT.4 Fluently add and subtract multi- digit whole numbers using strategies to include a standard algorithm.

10. 4-1 Mental Math Did estimating help you find an answer?
Estimating is one type of problem solving strategy for addition and subtraction.
Estimation does not come up with an exact answer
Estimation often uses rounding numbers
Mental math uses the things you “just know” to help you solve problems in your head
Students will need math textbook, math journal, and paper

11. Using Mental Math to Add and Subtract
Turn to page 90 in your math textbook and follow along, copy this into your journal
Commutative property of addition: add numbers in the order that is EASIEST, so x + y = y + x
Associative property of addition you can group numbers and add in any order, so (x+y)+z = x + (y+z)
Identity property of addition means that any number plus 0 is the same number, so X + 0 = X and Y + 0 = Y

12. Properties of Addition – So What?
The properties of addition make when and how we add numbers flexible!
Start with easy facts, break numbers apart, count on or up, and compensate to solve problems
is the same as
And the same as
And the same as
They all equal 183

13. I DO - Breaking Apart
Use fact families to split up bigger numbers and GET TO 10
Problem #1, page 91 is =
= 90
= = 111
Break Apart
Break Apart
Break Apart

14. WE DO – Try this!
In your Journal: Add using the “break-apart/get to 10” strategy

15. WE DO – Try this! Answers
is the same as: = = 112 How else can we do this?

16. X is used to represent what we DO NOT KNOW in a problem
Counting/Adding On
Use addition to help in subtraction
Problem # 3, page 91 is
566 – 359 = X = 566
So = 360
= 560
= 566
So = 566
And 566 – 359 = OR 566 – 359 = 207
X is used to represent what we DO NOT KNOW in a problem

17. WE DO – Try this!
In your Journal: Subtract using the “counting/adding on” strategy

18. WE DO – Try this! Answers
is the same as: 99 + X = = = = 122 So = 122 So 122 – 99 = 23

19. Compensation
Compensation combines rounding and addition or subtraction to solve problems
Problem # 5, page 91 :
It is really easy to add = 750
Since we added 1 to each number, now we subtract those 1’s 750 – 1 – 1 = 748
So = 750 – 1 – 1 = 748
START 9/21/15

20. In your Journal: Add 157 + 61 using the “compensation” strategy
WE DO – Try this!
In your Journal: Add using the “compensation” strategy

21. WE DO – Try this! Answers
can be changed to: = – 3 = 118 So = 118

22. YOU DO - Practice on your own
Open your MATH TEXTBOOK to Page 91 and complete problems 2, 4, 6, 7, 8, and (all) ON A PIECE OF LINED PAPER, work by yourself
If you finish early, use your MATH WORKBOOK and complete RETEACHING 4-1 and PRACTICE 4-1 as well.
After 5 minutes I will come to check on each table
TURN THIS IN BY THE END OF THE PERIOD

23. Reflect and Review MATH NOTES (Copy to your Math Journal)
In your math journal, write 3 sentences about which mental math strategies you like the best. Can you think of times in your everyday life that you use them?
MATH NOTES (Copy to your Math Journal)
Breaking Apart, Get to 10, Counting/Adding On, and Compensation are strategies that help us make addition and subtraction problems easy to solve in your head.
Pack up, you may take your MATH BOOK, MATH WORKBOOK, and MATH JOURNAL home.

24. GAME: Rounding Relay
Each team of 4-5 players gets a whiteboard, dry-erase marker, and eraser
A number will be called out/written on the board, one member of each team will stand at the front of the room, the rest are at the table
One player from each team will round the number to the nearest 10, 100, 1000, or 10,000 and hold up the board, if the answer is correct they will run back to their table and pass the board to the next player who will come back to the front
The first table/team to get all players back to their table wins

25. Rounding Relay
816
12,458
147,895
85,921
4,821

26. Addition & Subtraction
4.NSBT.4 Fluently add and subtract multi- digit whole numbers using strategies to include a standard algorithm.

27. 4-2 Estimating Sums and Differences
What is a sum?
What is a difference?
How does estimating help us here?
Turn to page 94 in your MATH TEXTBOOK and follow along!
I DO – Washington Monument Example

28. WE DO – Try This! Page 94, Problem #1 is 563 + 375 Let’s estimate!
I will round to the nearest 10, that will give me a close answer and can even be the first step in compensation
= = 940
Let me see how close I was: = 938
How could I have used compensation? =

29. WE DO – Try This! Page 94, Problem #3 is 645 + 253
Let’s estimate! RAISE YOUR HAND to help!
What place value should we round to? Why?
What new numbers would we get?
Let’s work the problem

30. YOU DO - Practice on your own
In your TEXTBOOK on pages 94 – 95, work the following problems: ALL EVEN problems 2-30

31. Reflect and Review
In your math journal, write 3 sentences about how rounding and compensation are similar and different.
MATH NOTES (Copy to your Math Journal)
When adding or subtracting we can use rounding to estimate an answer OR to check if our answer is reasonable
The steps for rounding:
Find the place value you need to round to
Look at the digit on the right, if it is 0-4 round down, 5-9 round up
THE PLACE VALUE you are rounding to will stay the same or go up by 1 digit
All the digits after the place value become 0 (zero)

32. GAME: Rounding Relay
Each team of 4-5 players gets a whiteboard, dry-erase marker, and eraser
A number will be called out/written on the board, one member of each team will stand at the front of the room, the rest are at the table
One player from each team will round the number to the nearest 10, 100, 1000, or 10,000 and hold up the board, if the answer is correct they will run back to their table and pass the board to the next player who will come back to the front
The first table/team to get all players back to their table wins

33. Rounding Relay
816
12,458
147,895
85,921
4,821

34. GAME: Adding Relay
Each team of 4-5 players gets a whiteboard, dry-erase marker, and eraser, the teacher will write 5 numbers on the board
At the team’s table one player will complete an addition problem and pass the board to the next team member who will add the next number to the original answer
The board will be passed to each teammate until all the numbers are added
The team will receive 1 point for each correct answer and a bonus if all the answers are correct

35. Adding Relay
+ 1,483
+ 24,948
+ 31
+ 899

36. Addition & Subtraction
4.NSBT.4 Fluently add and subtract multi- digit whole numbers using strategies to include a standard algorithm.

37. 4-4 Subtraction - Review
Subtraction reduces numbers (makes them smaller)
Subtraction can mean spending money, giving things away, or finding the difference
Subtraction is the opposite or INVERSE of addition
Use estimation to help make sure your answer is reasonable
Subtract from Left to Right

38. I DO - Subtraction
Turn to page 100 in your MATH TEXTBOOK and follow along as I do problem #1: 527 – 338
Estimate using rounding: 530 – 340 = 190
In my head, I used compensation to estimate:
– 340 = 200 – 10 = 190
Work the problem using borrowing:
17 – 8 = 9
11 – 3 = 8
4 – 3 = 1
The answer is 189
Compensation to Subtract: – 338 = 190 – 1 = 189

39. WE DO – Try this! 716 – 254 Now, let’s do 139 – 86 = And 1,268 – 429 =
How would we estimate the answer?
Is there a strategy we should use?
Will we have to borrow? How do you know?
Now, let’s do 139 – 86 =
And 1,268 – 429 =

40. WE DO – Try this! ANSWERS 716 – 254 = 462 139 – 86 = 53
How would we estimate the answer? 720 – 260 = 460
Is there a strategy we could use?
=500 as an estimation
=506-44=462
Will we have to borrow? How do you know?
Yes, because the 5 in the tens place is greater than the 1
139 – 86 = 53
1,268 – 429 = 839

41. YOU DO – Practice on your own
Go to pages in your textbook, work ALL ODD PROBLEMS 5 – 31 on a sheet of LINED PAPER
If you finish early, go to your MATH WORKBOOK and complete the RETEACHING 4-4 and PRACTICE 4-4, all problems.
TURN IN all COMPLETE work at the end of the period. Take your workbook and journal HOME.

42. Reflect and Review
In your MATH JOURNAL, write three sentences about what your brain is thinking while you are doing subtraction by answering the following questions.
Are you able to focus?
Do you solve most of the problem in your head?
Do you have to have paper?
Is subtraction easier than addition? Why or why not?
Math Notes: (copy into your journal)
Subtraction is the INVERSE, or opposite, of addition and shows a DECREASE in value
Subtraction problems use words like: difference, less than, sold, gave away, and decrease

43. GAME: Subtraction Relay
Each team of 4-5 players gets a whiteboard, dry-erase marker, and eraser, the teacher will write 5 numbers on the board
At the team’s table one player will complete an addition problem and pass the board to the next team member who will subtract the next number from the original answer
The board will be passed to each teammate until all the numbers are subtracted
The team will receive 1 point for each correct answer and a bonus if all the answers are correct

44. Subtraction Relay
69,
- 1,083
- 24,948
- 310
- 899

45. Addition & Subtraction
4.NSBT.4 Fluently add and subtract multi- digit whole numbers using strategies to include a standard algorithm.

46. 4-5 Subtracting Across Zeros
This is still subtraction, but what do you do when there is a Zero in your way?
Follow along in your textbook on page 102
I DO – Page 102, Problem #1:

47. WE DO – Try this! Page 102, problem # 2 is 1,086 – 728
Estimate by rounding: 1100 – 700 = 400
Use compensation:
1, – 728
1,090 – 728 = 362 – 4 = 358
Check using addition: = 1,086
Or use regular subtraction:
16 – 8 = 8
7 – 2 = 5
10 – 7 = 3
So the answer is 358

48. WE DO – Try this!
810 – 638
How would we estimate the answer?
Is there a strategy we should use?
Will we have to borrow? How do you know?
3,304 – 1,137
1,001 – 868

49. WE DO – Try this! ANSWERS 810 – 638 3,304 – 1,137 = 2,167
How would we estimate the answer?
810 – 640 OR
Is there a strategy we should use?
Will we have to borrow? How do you know?
Yes, because we are subtracting from a 0 in the ones place
3,304 – 1,137 = 2,167
1,001 – 868 = 133

50. YOU DO – Practice on your own
Turn to pages in your MATH TEXTBOOK, on a piece of lined paper, complete problems 9-12, problems 21-24, and problems
If you finish early, please go to your MATH WORKBOOK and complete RETEACHING 4-5 and PRACTICE 4-5.
Turn in ALL COMPLETED WORK at the end of the period.

51. Review and Reflect
In three sentences, explain what mistakes people might commonly make when subtracting from a number that has more than 1 zero in it.
MATH NOTES (copy into your MATH Journal)
Subtraction strategies are similar to addition strategies. While ADDING you carry over to the next highest value(to the LEFT), when you subtract you take ten TO THE RIGHT.