MATHEMATICS GRADE 5 TOPIC: MULTIPLICATION ......2008/06/10 · GET DIRECTORATE Page 8 of 15 Grade 5 Multiplication,ratio and rate MEMORANDUM: HOMEWORK DBE workbook Exercise 49 page

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Grade 5 Multiplication,ratio and rate

TOPIC: MULTIPLICATION, RATIO AND RATE

DAY 1

CLASS ACTIVITY: Complete the activities in your Maths workbook. Use the

memorandum to check your work.

Mental Maths

1. Complete the following exercise in your workbook. Write down only the answers.

30 × 8 = 30 × 5 = 90 x 10 =

20 × 9 = 80 × 8 = 60 x 6 =

80 × 6 = 20 × 7 = 50 x 5 =

90 × 7 = 20 × 4 = 50 x 50 =

30 × 2 = 90 × 2 = 80 x 9 =

20 × 6 = 90 x 20 = 60 x 40 =

Multiply 3-digit numbers with 1-digit numbers. Study the following example:

2. Use the above method and do the following in your workbook.

(a) 563 × 7 (b) 6 × 378

(c) 7 × 493 (d) 908 × 8

Watch the following video (3- digit x 1-digit) if you still do not understand the method.

Click on the video icon

Break up the first number.

347 x 8 can be calculated as follows:

347 x 8 = (300 + 40 + 7) x 8

Thus, 347 x 8 = 300 x 8 + 40 x 8 + 7 x 8

= 2 400 + 320 + 56

= 2 000 + 400 + 300 + 20 + 50 + 6

= 2 766

MATHEMATICS

GRADE 5

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HOMEWORK: Complete the activities in your Maths workbook. Use the memorandum to

check your work.

3. One hotel has 238 rooms. How many rooms are there in 7 such hotels?

4. Jane needs to feed eight two-week-old baby goats 375 ml of milk each, four times a day.

How much milk does she need every day? Give your answer in milliliters.

5. A bag of onions has a mass of 875 g. Calculate the total mass of eight bags of onions.

Give your answer in kilograms.

MEMORANDUM: CLASSWORK

1.

30 × 8 = 240 30 × 5 = 150 90 x 10 = 900

20 × 9 =180 80 × 8 = 640 60 x 6 = 360

80 × 6 = 480 20 × 7 = 140 50 x 5 = 250

90 × 7 = 630 20 × 4 = 80 50 x 50 = 2 500

30 × 2 = 60 90 × 2 = 180 80 x 9 = 720

20 × 6 = 120 90 x 20 = 1 800 60 x 40 = 2

2. (a) 563 × 7 = 500 x 7 + 60 x 7 + 3 x 7

= 3 500 + 420 + 21

= 3 000 + 500 +400 + 20 + 20 + 1

= 3 941

(b) 6 × 378 = 6 x 300 + 6 x 70 + 6 x 8

= 1 800 + 420 + 48

=1 000 + 800 + 400 +20 + 40 + 8

= 2 200 +60 + 8

= 2 268

(c) 7 × 493 = 7 x 400 + 7 x 90 + 7 x 3

= 2 800 +630 + 63

= 2 000 + 800 + 600 + 30 + 60 + 3

= 3 493

(d) 908 × 8 = 900 x 8 + 8 x 8

= 7 200 + 64

= 7 000 + 200 + 60 + 4

= 7 264

MEMORANDUM: HOMEWORK 3. Number of rooms: 238 x 7 = 1 666

4. Quantity of milk: 4 x 8 x 375 = 12 000 ml

5. Mass: 875 x 8 = 7 000 g = 7 kg

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CLASS ACTIVITY: Complete the activities in your Maths workbook. Use the


Mental Maths

1. Complete the following exercise in your workbook. Write down only the answers

30 × 80 = 30 × 20 = 80 × 800 =

20 × 90 = 30 × 50 = 90 × 200 =

80 × 60 = 20 × 7= 90 × 50 =

90 × 70 = 80 × 10 = 90 x 500 =

30 × 10 = 90 × 80 = 80 x 70 =

20 × 40 = 20 × 600 = 90 x 100 =

Today you are going to learn how to multiply a 3-digit number with a 2-digit number

Study the following example:

Example: 143 x 24 = 3 432

1 4 3

x 2 4

1 2 4 x 3

1 6 0 4 x 40

4 0 0 4 x 100

6 0 20 x 3

8 0 0 20 x 40

2 0 0 0 20 x 100

3 4 3 2

Use the method above and do the following in your workbook.

(a) 384 × 76 (b) 34 × 328

Watch the following video (3- digit x 2-digit_vertical column method) if you still do not

understand the method.


HOMEWORK:

Do activity in your Maths workbook. Use the memorandum to check your work.

If you really want to fully understand this method, you can do the

following activity in your DBE workbook. Exercise 44a page 129 nr 3a and 3b.

Use method as explained in example 2.

DAY 2

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1.

30 × 80 = 2 400 30 × 20 = 600 80 × 800 = 64 000

20 × 90 = 1 800 30 × 50 = 1 500 90 × 200 = 18 000

80 × 60 = 4 800 20 × 7 = 140 90 × 50 = 4 500

90 × 70 = 6 300 80 × 10 = 800 90 x 500 = 45 000

30 × 10 = 300 90 × 80 = 7200 80 x 70 = 5 600

20 × 40 = 800 20 × 600 = 12 000 90 x 100 = 9 000

2a. 384 × 76 = 29 184

3 8 4

x 7 6

2 4 6 x 4

4 8 0 6 x 80

1 8 0 0 6 x 300

2 8 0 70 x 4

5 6 0 0 70 x 80

2 1 0 0 0 70 x 300

2 9 1 8 4

2b. 34 × 328 = 11 152

3 2 8

3 4

3 2 4 x 8

8 0 4 x 20

1 2 0 0 4 x 300

2 4 0 30 x 8

6 0 0 30 x 20

9 0 0 0 30 x 300

1 1 1 5 2

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HOMEWORK: MEMORANDUM -DBE WORKBOOK EX 44A PAGE 3a. 168 x 34 = 5 712

1 6 8

3 4

3 2 4 x 8

2 4 0 4 x 60

4 0 0 4 x 100

2 4 0 30 x 8

1 8 0 0 30 x 60

3 0 0 0 30 x 100

5 7 1 2 3b. 219 x 49 = 10 731

2 1 9

4 9

8 1 9 x 9

9 0 9 x 10

1 8 0 0 9 x 200

3 6 0 40 x 9

4 0 0 40 x 10

8 0 0 0 40 x 200

1 0 7 3 1

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CLASS ACTIVITY: Complete the activities in your workbook. Use the memorandum to check your work. Mental Maths

1. Complete the following exercise in your workbook. Write down only the answers.

30 × 80 = 80 × 70 = 20 × 700 =

20 × 90 = 90 × 80 = 900 × 100=

80 × 60 = 30 × 200 = 800× 10 =

90 × 70 = 30 × 500 = 900 × 5 =

30 × 10 = 20 × 600 = 90 × 200 =

20 × 40 = 80 × 800 =

Today we are going to use another method to multiply a 3-digit number with a 2-digit

number. This method is called the box method or area model.

Look at the following example:

143 x 24 = 3 432

x 100 40 3 Add the numbers

20 2 000 800 60 2 860 (2000 + 800 + 60)

4 400 160 12 572 (400 + 160 +12)

2 400 960 72 3 432 (2 400 + 960 + 72)

2. Use the method above and do the following in your workbook.

(a) 324 × 23 (b) 415 x 36

Watch the following video (3- digit x 2-digit_area model) if you still do not understand the method.


Break up 143 and 24

DAY 3

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HOMEWORK

1. If you really want to fully understand this method, you can do the

Following activity in your DBE workbook.

Exercise 49 page 140 nr 1a and 1b

Use the table method (also called the box method or area model)

2. The entrance fee for a concert is R48 for adults. Tickets are sold at the door. How much

money is taken at the door if 467 adults attend the concert?

3.(a) On a strawberry farm, there are 546 strawberry plants in each bed. How many plants are

there altogether in 34 strawberry beds?

(b) Strawberry jam is also produced on the farm and packed in boxes of 48 jars each. How

many jars are there in 465 boxes?

MEMORANDUM: CLASSWORK 1.

30 × 80 = 2 400 800 × 70 = 56 000 20 × 700 = 14 000

200 × 90 =18 000 90 × 800 = 72 000 900 × 100= 90 000

80 × 60 = 4 800 30 × 200 = 6 000 800× 100 =80 000

90 × 70 = 6 300 30 × 500 =15 000 900 × 50 =45 000

30 × 100 = 3 000 20 × 600 =12 000 90 × 200 =18 000

20 × 400 = 8 000 80 × 800 = 64 000

2a. 324 × 23 = 7 452

x 300 20 4

20 6 000 400 80 6 480

3 900 60 12 972

6 900 460 92 7 452

2b. 415 x 36 = 14 940

x 400 10 5

30 12 000 300 150 12 450

6 2 400 60 30 2 490

14 400 360 180 14 940

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MEMORANDUM: HOMEWORK DBE workbook Exercise 49 page 140

1a. 578 x 25 = 14 450

1b.967 x 29 = 28 043

2. Amount = 467 x R28

= R 13 076

3(a) Number of plants = 546 x 34

=18 564

(b) Number of jars = 465 x 48

= 22 320

x 500 70 8

20 10 000 1 400 160 11 560

5 2 500 350 40 2 890

12 500 1 750 200 14 450

x 900 60 7

20 18 000 1 200 140 19 340

9 8 100 540 63 8 703

26 100 1 740 203 28 043

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DAY 4

CLASS ACTIVITY: RATIO is the comparison of two or more similar quantities.

Carefully read the following passage:

I have a lawnmower that runs on fuel and two stoke oil. I mix the fuel and oil in the ratio 25:1.

What does it mean? It means that for every 25 ml of fuel I must add 1 ml of oil. Therefore, if I

put 100ml of fuel in the lawnmower, I must add 4ml of oil. We read 25:1 as “25 to 1”. We can

also write it as 𝟐𝟓

𝟏 .

Study the following diagram.

(a) How many blocks are grey? There are 2 grey blocks.

(b) How many blocks are white? There are 3 white blocks.

(c) What is the ratio of grey blocks to white blocks? Ratio is 2:3 ( 𝟐

𝟑 )

(d) What is the ratio of white blocks to grey blocks? ratio is 3:2 ( 𝟑

𝟐 )

FUEL

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Classwork: Do the following exercise in your Maths workbook. Use the memorandum to

check your work.

Look closely at the two pictures above. Picture 2 is the same as

Picture 1, only much larger. All the parts have been drawn bigger in

the same way.

1. A picture of another house is drawn bigger, so that it is 6 times as big.

(a) If a window is 5 mm high in the small picture, how high is it in the big picture?

(b) If a door is 120 mm high in the big picture, how high is it in the small picture?

(c) If the house is 192 mm high in the big picture, how high is it in the small picture?

2. When he walks, Isaac takes 12 steps each minute while Benjamin

takes 20 steps.

(a) What is the ratio between the numbers of steps they take in one minute?

(b) How many steps will Benjamin take while Isaac takes 6 steps?

(c) How many steps will Isaac take while Benjamin takes 30 steps?

a. How many peaches do you see?

b. How many bananas do you see?

c. What is the ratio of bananas to peaches?

d. What is the ratio of peaches to bananas?

e. What is the ratio of peaches to all the fruit?

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HOMEWORK: Complete the activity in your workbook. Use the


1. Study the picture of the flowers and answer the questions:

a. How many pink flowers do you count?

b. How many yellow flowers do you count?

c. How many purple flowers do you count?

d. How many white flowers do you count?

e. What is the ratio of white flowers to pink flowers?

f. What is the ratio of yellow flowers to purple flowers?

g. What is the ratio of pink flowers to white flowers?

h. What is the ratio of yellow flowers to all the flowers?

i. What is the ratio of purple flowers to all the flowers?


1(a) 5 mm x 6 = 30 mm

(b) 120 mm ÷6 = 20 mm

(c) 192 mm ÷ 6 = 34 mm

2. (a) 12:20

(b) 10 treë

(c) 18 treë (30 ÷ 5 x 3)of 3

5 𝑣𝑎𝑛 30

3. (a) 2

(b) 3

(c) 3:2

(d) 2:3

(e) 2:5

White

e

Yellow

Yellow

Pink Pink

Pink White

e Purple

Purple Purple

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MEMORANDUM: HOMEWORK

1 (a) 3

(b) 2

(c) 3

(d) 2

(e) 2:3

(f) 2:3

(g) 3:2

(h) 2:10

(i) 3:10

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DAY 5

CLASS ACTIVITY

Today you will learn about the concept of RATE. Rate describes the

relationship between two or more quantities that are measured in different

units.

Explanation

We are exposed to rate in everyday life. Look at the pictures and labels below.

The price of chicken is R42 per kg.What does per “per kg” mean?

It means that one kliogram costs R42.

The Snowflake cake flour costs R25 for 2kg.

What does one kilogram cost? R25 ÷ 2= R12,50

The box of Weet-Bix costs R36 for 900 g. How much will you pay for 100g? R36 ÷ 9= R4

How much will 1 kg Weetbix cost? R4 x 10 = R40

100 g costs R4.

Therefore1 000 g costs R40 (multiply by 10, because 10 x 100 = 1 000. 1000 g = 1 kg)

These are all examples of rate.

R25

2 kg R42,00

per kg

R36,00

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Homework: Do you the activity in your Maths workbook. Use the memorandum to check your

work.

Study the advertisements below and answer the questions.

1. How many eggs in a dozen? 2. How much does one dozen of eggs cost?

3. How much does 4 dozen of eggs cost?

4. How much does two and a half dozen of eggs cost?

5. How much does 2 packets of White Star maize meal cost?

6. How much does10 kg maze meal cost?

7. What does one 1kg maze meal cost?

8. How much does one litre of milk cost?

9. How much does three litres of milk cost?

10. How much will it cost you if you buy two of each item as shown above?

11. How much change will you get if you pay with six R50 notes?


1. 12 eggs

2. R18 x 2 = R 36

3. R36 x 4 = R144

4. R18 x 5 = R90

5. R20 x 2 = R40

6. R20 x 4 = R80 (2,5kg x 4 = 10kg)

7. R10 (10 kg costs R80, therefore 1 kg costs R10)

8. R72 ÷ 6 = R12

9. R12 x 3 = R36

10. (2 x R18) + (2 x R20) + (2 x R72)

= R36 + R40 + R144

= R220

11. Change = (6 x R50) – R220 = R330 - R220 = R80

R20

2,5 kg

R18 / 1

2 dozen

R72,00

6x1 litre

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MEMORANDUM: HOMEWORK

. (a) R52 ÷ 2 = R26

(b) 500 g = 1

2 kg

If 1 kg = R26

Then 1

2 kg = R13 (26 ÷ 2 =13)

(c) R52 x 5 = R260 (d)

1

2 van R28 = (R28 ÷ 2) x 1

= R14

(e) R26 x 3 = R78

(f) 250 = 1

4 𝑘𝑔

Therefore 1

4 of R28 = (R28 ÷ 4) x 1

= R7

(g) Costs = (2 x R28) + (4 x R26) + (3 x R52)

= R56 + R104 + R156

= R316

Change = (2 x R200) – R316

= R400 – R316

= R84

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MATHEMATICS GRADE 5 TOPIC: MULTIPLICATION ......2008/06/10 · GET DIRECTORATE Page 8 of 15 Grade 5 Multiplication,ratio and rate MEMORANDUM: HOMEWORK DBE workbook Exercise 49 page