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Year 5 Term 2 Unit 9 Day 1

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Year 5 Term 2 Unit 9. Day 1. L.O.1 To be able to add and subtract any pair of two-digit numbers. 30+40 Write the answer in your books. Q. How did you work that out? We can get the answer using: the number fact 3 + 4 and then applying place value x 10 - PowerPoint PPT Presentation

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Page 1: Year 5 Term 2 Unit 9

Year 5 Term 2 Unit 9

Day 1

Page 2: Year 5 Term 2 Unit 9

L.O.1

To be able to add and subtract any pair of two-digit numbers

Page 3: Year 5 Term 2 Unit 9

30+40

Write the answer in your books.

Page 4: Year 5 Term 2 Unit 9

Q. How did you work that out?

We can get the answer using: the number fact 3 + 4 and then applying place value x 10

We can use a similar method for subtractionLOOK….

50 – 20The number fact is 5 – 2

And the place value is x 10

Page 5: Year 5 Term 2 Unit 9

Try these using the same method where possible:

80 – 50

70 + 4034 + 54

75 – 4046 + 52

58 – 2580+ 40

Page 6: Year 5 Term 2 Unit 9

In your book write synonyms for:

+ -

Page 7: Year 5 Term 2 Unit 9

L.O.2

To be able to add or subtract the nearest multiple of 10 ,100 or 1000 then adjust.

Page 8: Year 5 Term 2 Unit 9

Round these numbers:1. To the nearest 10

34 27 78 66 552. To the nearest 100 167 761 354 855 213. To the nearest 1000

2435 7328 4982 6525 7721

Write in your books how much we had to adjust each number by.

Page 9: Year 5 Term 2 Unit 9

We can use rounding as a strategy for addition and subtraction.

93 – 69Thus:1. What multiple of 10 is nearest to 69?• What is 93 – 70?• Have we subtracted more or less than

69?• How should we adjust the answer to

make it correct?

Page 10: Year 5 Term 2 Unit 9

Our sum is:

93 – 69 = ( 93 – 70 ) + 1

= 23 + 1

= 24

This can be shown on a number line.

23 24 93

+1 -70

Page 11: Year 5 Term 2 Unit 9

Our sum is now:

93 – 69 = ( 93 – 70 ) + 1

= 23 + 1

= 24

This can be shown on a number line.

23 24 93

-70

+ 1

Page 12: Year 5 Term 2 Unit 9

We are going to try this: 368 + 51.

368 + 51 = (368 + 50) + 1

= 418 + 1

= 419

Draw the number line in your books.

368 418 419

+50 +1

Page 13: Year 5 Term 2 Unit 9

Try this:

286 – 97 = (286 – 100) + 3

= 186 + 3

= 189

We need a volunteer to draw the number line!

Page 14: Year 5 Term 2 Unit 9

Try this:

5250 – 1998 = (5250 – 2000) + 2

= 3250 + 2

= 3252 We need a volunteer to draw the number line

Page 15: Year 5 Term 2 Unit 9

Try this

458 + 199 = (458 + 200) – 1

= 658 – 1

= 657 We need a volunteer to draw the number line

Page 16: Year 5 Term 2 Unit 9

Do these :

include the written sum and the number line.

All groups: + Spheres + Prisms

289 – 98 756 – 197 2348 – 1996

645 + 69 572 + 196 5932 + 2995

584 – 97 615 - 498 3688 - 1994

1267 + 88 1546 + 997 5482 + 1988

Page 17: Year 5 Term 2 Unit 9

Look at these:

73 + 26 182 – 95

6003 – 5994 56 – 29

73 + 200 583 – 71

• For which of these would you use the rounding and adjusting strategy?

Q . How would you tackle the other questions?

Page 18: Year 5 Term 2 Unit 9

By the end of the lesson the children should be able to:

For example, work out mentally that:274 + 96 = 370

as 274 + 100 – 4 = 374 – 4 = 370

and 4005 – 1997 = 2008 as 4005 – 2000 + 3

Page 19: Year 5 Term 2 Unit 9

Year 5 Term 2 Unit 9

Day 2

Page 20: Year 5 Term 2 Unit 9

L.O.1

To be able to recall addition and subtraction facts for each number to 20 and extending to

multiples of 10.

Page 21: Year 5 Term 2 Unit 9

Write the answer in your books to the following:

15 – 7 12 + 8 9 + 8 3 + 4

7 + 6 11 + 11 14 – 5

12 – 4 6 + 13 8 – 5 17 + 6

19 – 10

Page 22: Year 5 Term 2 Unit 9

Q. What strategies can we use for quick recall?

We can : 1. double and subtract or add

e.g. 6 + 7 = 6 + 6 +12. round up or down and subtract or add the difference

e.g. 8 + 12 = 8 + 10 + 2• Subtract even numbers by halving it and subtracting it

twicee.g. 16 – 4 = 16 – 2 - 2

Page 23: Year 5 Term 2 Unit 9

We can use the same strategies with multiples of 10.

Do these in your book:

70 + 60 10 +20 140 – 50 190 – 100

Can you see the similarities?

Page 24: Year 5 Term 2 Unit 9

Q. Did you see the similarities?

Q. What strategies did you use?

Page 25: Year 5 Term 2 Unit 9

L.O.2

To be able to add several numbers.

Page 26: Year 5 Term 2 Unit 9

40 + 90 + 60 + 50

Copy these numbers into your book as they are here and calculate the total.

Q. How did you find the total?

Page 27: Year 5 Term 2 Unit 9

To find the total we can;

1. look for numbers that sum 100

60 + 402. start with the largest number first

90 + 60 +

Page 28: Year 5 Term 2 Unit 9

Now try these:

60 + 70 + 20 + 80 + 20 + 30 + 80 + 70

50 + 60 + 30 + 80 + 40 + 90 + 40 + 50

Q. What strategies did you use?

Page 29: Year 5 Term 2 Unit 9

Look at this calculation:

63 + 15 + 35

Q. What strategies do you use?

Page 30: Year 5 Term 2 Unit 9

To find the total we can;

1. look for unit pairs that make 10

35 + 152. start with the largest number first

63 + 35

Page 31: Year 5 Term 2 Unit 9

1 + 2 + 3 + 4 + 5 + 5+ 6 + 7 + 8 + 9

Copy these numbers into your book and add them up.

Remember to use pairing strategy.

Page 32: Year 5 Term 2 Unit 9

The answer is 50.

Page 33: Year 5 Term 2 Unit 9

Q. How many pairs of numbers sum to 10?

1 + 2 + 3 + 4 + 5 + 5+ 6 + 7 + 8 + 9

= 5 X 10

Page 34: Year 5 Term 2 Unit 9

Look at this calculation:

4 + 4 + 3 + 5

Q. What multiplication is this equivalent to?

Page 35: Year 5 Term 2 Unit 9

To find the answer we must first do the calculation using our addition strategies.

4 + 4 + 3 + 5 = 16

16 is the equivalent to 4 X 4

Q Who got this right?

Page 36: Year 5 Term 2 Unit 9

Q. How can we represent the following as a multiplication?

18 + 20 + 22

Page 37: Year 5 Term 2 Unit 9

To find the answer we must first do the calculation using our addition strategies.

18 + 20 + 22When we look at the numbers we can see that

18 and 22 make 40 ; a multiple of 2020 is also a multiple of 20

That means that there are 3 multiples of 20 so 60 is the equivalent to 20 X 3

Page 38: Year 5 Term 2 Unit 9

Let’s look at this one

48 + 49 + 50 + 51 + 52

Q. What strategies could we use to find the sum?

Page 39: Year 5 Term 2 Unit 9

To find the total we can;1. look for numbers that sum 100

48 +522. start with the largest number first

52 + 51 +3. look for multiples

504. look for unit pairs of 10

51 + 49

Page 40: Year 5 Term 2 Unit 9

Showing your method, do the following in your books:

18 + 19 + 20 + 21 + 22

26 + 28 + 30 + 32 + 34

64 + 66 + 70 + 74 + 76

83 + 85 + 90 + 97 + 95

Page 41: Year 5 Term 2 Unit 9

Q. What strategies did you use to find the answers?

Q. Which strategy do you think is best for this calculation?

18 + 19 + 20 + 21 + 22

Page 42: Year 5 Term 2 Unit 9

Copy this into your books

20 2 49 23

86 17 64 50

60 38 21 7

40 16 62 42

Page 43: Year 5 Term 2 Unit 9

In your books write down sets of numbers from the table that you can total using all the addition strategies we have looked at today.

Page 44: Year 5 Term 2 Unit 9

Year 5 Term 2 Unit 9

Day 3

Page 45: Year 5 Term 2 Unit 9

L.O.1

To be able to add near doubles including decimals.

Page 46: Year 5 Term 2 Unit 9

Look at this calculation

35 + 36

Q What strategy could you use to find the sum?

Look at the numbers, they are near doubles of each other.

Page 47: Year 5 Term 2 Unit 9

To calculate the sum we simply have to double one of the numbers and adjust the answer.

E.g. 35 + 36 = (35 x 2) +1

70 + 1 = 71

OR

35 + 36 = (36 x 2) -1

72 – 1 = 71

Page 48: Year 5 Term 2 Unit 9

Try these using one or all of the near doubling strategies:

41 + 42 =85 + 82 =53 + 50 =11 + 15 =

Page 49: Year 5 Term 2 Unit 9

Now work out these calculations

17 + 16 and 1.7 + 1.6

Q. How did you work them out?

Page 50: Year 5 Term 2 Unit 9

To find the sum of 16 + 17 we double and adjust the numbers.

16 x 2 = 32

32 + 1 = 33

If 16 is the same as 1.6 x 10

and 17 is the same as 1.7

Q. How can this help us work out 1.6 + 1.7?

Page 51: Year 5 Term 2 Unit 9

The answer is simple.

If 16 +17 = 33

then 1.6 + 1.7 = 3.3

We have divided 33 by 10

OR

moved the decimal point one place to the left.

Page 52: Year 5 Term 2 Unit 9

In your books work out the following using the same method

12 + 13 1.2 + 1.3

25 + 24 2.5 +2.4

44 + 43 4.4 + 4.3

TiP : do the whole numbers first

Page 53: Year 5 Term 2 Unit 9

The answers are:

25 2.5

49 4.9

87 8.7

Page 54: Year 5 Term 2 Unit 9

L.O.2

To be able to add several numbers using a variety of strategies for mental addition.

To solve mathematical problems or puzzles, recognise and explain patterns and

relationships.

Page 55: Year 5 Term 2 Unit 9

Look at this table

13 18 11

12 14 16

17 10 15

Page 56: Year 5 Term 2 Unit 9

What is the total for this column and this row?

13 18 11

12 14 16

17 10 15

Page 57: Year 5 Term 2 Unit 9

What do you notice about the totals?

13 18 11

12 14 16

17 10 15

Page 58: Year 5 Term 2 Unit 9

Yes. They all add up to 42!!

13 18 11

12 14 16

17 10 15

Page 59: Year 5 Term 2 Unit 9

Are there any other patterns?

13 18 11

12 14 16

17 10 15

Page 60: Year 5 Term 2 Unit 9

Look at these numbers

13 18 11

12 14 16

17 10 15

Page 61: Year 5 Term 2 Unit 9

This known as a 3 x 3 magic square.

13 18 11

12 14 16

17 10 15

Page 62: Year 5 Term 2 Unit 9

Q What do you think would happen if we subtract 7 from each number?

Would it still be a magic square?

Page 63: Year 5 Term 2 Unit 9

Let’s check. What is the ‘magic’ total for the square now?

6 11 4

5 7 9

10 3 8

Page 64: Year 5 Term 2 Unit 9

Yes. It is 21.How could we have predicted this happening?

6 11 4

5 7 9

10 3 8

Page 65: Year 5 Term 2 Unit 9

Would the square still be magic if we aded or subtracted ANY number from each

square?

13 18 11

12 14 16

17 10 15

Page 66: Year 5 Term 2 Unit 9

It would have to be the same number from each square.

13 18 11

12 14 16

17 10 15

Page 67: Year 5 Term 2 Unit 9

Let’s look at the number patterns with some different numbers.

Page 68: Year 5 Term 2 Unit 9

Q What do you notice about the answers we have found each square that we have tried?

Page 69: Year 5 Term 2 Unit 9

Each answer we have had has been a multiple of 3!

13 18 11

12 14 16

17 10 15

Page 70: Year 5 Term 2 Unit 9

The total we found (42) is 14 X 3.

13 18 11

12 14 16

17 10 15

Page 71: Year 5 Term 2 Unit 9

Remember when we subtracted 7 from each number? The total (21) is 3 x 7…MAGIC

6 11 4

5 7 9

10 3 8

Page 72: Year 5 Term 2 Unit 9

What is the sum of the first row and column?

17 10 15 4

14 5 16 11

8 19 6 13

7 12 9 18

Page 73: Year 5 Term 2 Unit 9

It is 46. Is this a multiple of 4?

17 10 15 4

14 5 16 11

8 19 6 13

7 12 9 18

Page 74: Year 5 Term 2 Unit 9

No. It isn’t.

17 10 15 4

14 5 16 11

8 19 6 13

7 12 9 18

Page 75: Year 5 Term 2 Unit 9

Do all the rows and columns total 46?

17 10 15 4

14 5 16 11

8 19 6 13

7 12 9 18

Page 76: Year 5 Term 2 Unit 9

Yes they do. Can you find any sets of 4 numbers that total 46?

17 10 15 4

14 5 16 11

8 19 6 13

7 12 9 18

Page 77: Year 5 Term 2 Unit 9

Let’s have a look at some.

17 10 15 4

14 5 16 11

8 19 6 13

7 12 9 18

Page 78: Year 5 Term 2 Unit 9

This is made up of 4 magic squares put together.

17 10 15 4 17 10 15 4

14 5 16 11 14 5 16 11

8 19 6 13 8 19 6 13

7 12 9 18 7 12 9 18

17 10 15 4 17 10 15 4

14 5 16 11 14 5 16 11

8 9 6 13 8 9 6 13

7 12 9 18 7 12 9 18

Page 79: Year 5 Term 2 Unit 9

Do these numbers add up to 46?

17 10 15 4 17 10 15 4

14 5 16 11 14 5 16 11

8 19 6 13 8 19 6 13

7 12 9 18 7 12 9 18

17 10 15 4 17 10 15 4

14 5 16 11 14 5 16 11

8 9 6 13 8 9 6 13

7 12 9 18 7 12 9 18

Page 80: Year 5 Term 2 Unit 9

Q Will every diagonal of 4 total 46?

On your on sheet highlight 4 diagonals and test.

Page 81: Year 5 Term 2 Unit 9

Let’s look at some of your answers.

17 10 15 4 17 10 15 4

14 5 16 11 14 5 16 11

8 19 6 13 8 19 6 13

7 12 9 18 7 12 9 18

17 10 15 4 17 10 15 4

14 5 16 11 14 5 16 11

8 9 6 13 8 9 6 13

7 12 9 18 7 12 9 18

Page 82: Year 5 Term 2 Unit 9

L.O.2

To be able to add several numbers using a variety of strategies for mental addition.

To solve mathematical problems or puzzles, recognise and explain patterns and

relationships.