MATHEMATICS GRADE 41)Te… · Thando’s height is 145 cm. Nazli’s height is 132 cm. Jessica’s height is 135 cm. (b) Who is the tallest? Waldo – 157 cm (c) Who is the shortest?

TOPIC:

Length TERM 2 MAIN RESOURCE:

Sasol-Inzalo Textbook

For learners: How to use the lessons:.

Introduction:

o

MATHEMATICS

GRADE 4

Hallo buddies. Here are a few steps to

show you how to make use of the

lessons.

Step 1: Look at the videos in the example.

Step 2: Do an exercise every day until you have

worked through all the days.

Step 3: Then do the informal exercise on the

last day to see if you understand the

work.

Step 4: At the end of each exercise you can mark your

work and see if you understand the work.

People need to agree on how big

things should be, such as homes, roads

and other things needed.

Otherwise there is big

trouble!

Day 1: Compare and measure lengths

Example: Who is the tallest? (Look at the video)

Meet Senzo and Temba. They are cousins and stay

in the same house.

Senzo Themba

Today they must

measure the

following, but not

one of them have a

ruler.

The distance from the top of the

right ear, over the head to the top

of the left ear.

2. The length of their

right foot.

3. The width of their left hand

span.

4. .

They must estimate

the answer before

they can measure it.

Senzo measure with a string.

His string is 3 matchstick long.

1. The distance over his head from ear

to ear is _________

2. The length of his right foot is

_______

3. The width of his left hand span

is_____

Senzo

Themba Themba measures with a matchstick.

1. The distance over his head from ear to

ear is______________

2. The length of his right foot is ____

__________________

3. The width of his left hand span

is ______________

Exercises: Do the following exercise in your notebook.

1. Think of Senzo and Themba’s story.

(a) Is there another way you would do the homework if you did not have a ruler?

Name it.

(b) Where could Senzo perhaps make a mistake with his measurement?

(c) Where could Themba perhaps make a mistake with his measurement?

(d) Which body part of Senzo is the longest?

(e) Which body part of Themba is the longest?

(f) Which body part, both measured, is the shortest?

(g) Which one would you use to measure the table top? The hand span or foot?

(h) Which one would you use to measure the length of the kitchen? The hand span

or foot?

(i) Will Senzo and Themba get the same answers if each of them measures the

table top and the length of the kitchen? Explain why.

(j) Which one would you use to measure the line below:

The matchstick or the string? Why?

(k) How many matchsticks do you estimate is the line? (Use Themba’s matchstick

as a measuring unit)

2. Which one of the following pairs is the longest? You can estimate the answer.

(a) The height of the front door of your home or the height of the table.

(b) The length of the netball court or the length of the rugby field?

(c) Your height or your teacher’s height?

(d) The length of the stoep or the width of the stoep in front of your class?

Day 1: Memorandum / Answers. Mark your work

1. Think about Senzo and Themba’s story.

a) Is there another way you would do the homework if you did not have a ruler? Name it.

Yes,

With a match box,

A piece of carton,

A new eraser,

A pritt stick.

b) Where could Senzo perhaps make a mistake with his measurement?

By not pulling the string tight every time, or

By not putting the one end of the string close to the other end of the string whilst

measuring.

He had to remember that the 3 matchsticks are long and that he had to count in

threes.

c) Where could Themba perhaps make a mistake with his measurement?

He did not put the matchsticks close together.

He did not make a mark at the end of the matchstick before picking it up every

time.

d) Which body part of Senzo is the longest?

The distance over his head from ear to ear.

e) Which body part of Themba is the longest?

The distance over his head from ear to ear.

f) Which body part, both measured, is the shortest?

The hand span

g) Which one would you use to measure the table top? The hand span or foot?

The hand span

h) Which one would you use to measure the length of the kitchen? The hand span or foot?

The foot

i) Will Senzo and Themba get the same answers if each of them measures the table top

and the length of the kitchen? Explain why.

No, the size of their hands and feet differs, or

Yes, the size of their hands and feet are the same.

j) Which one would you use to measure the line below?

The matchstick or the string? Why?

The string

The string is flexible. It will measure all the twists.

The matchstick is straight. It cannot measure twists easily.

k) How many matches do you estimate is the line? (Use Temba’s matchstick as a measuring

unit)

At least 5 matchsticks.

2. Which of the following pairs is the longest? You can estimate the answer.

(a) The height of the front door of your home or the height of the table.

The height of the front door

(b) The length of the netball court or the length of the rugby field?

The length of the rugby field

(c) Your height or your teacher’s height?

Your teacher’s height

(d) The length of the porch or the width of the porch infront of your class?

The length of the stoep

Day 2: Standard units of measurement

Introduction: (Look at video 2 – Standard unit of measurement)

The units that many people around the world use

are called standard units

This system is called the System of International Units (SI)

Here are some of the instruments used.

(a) A ruler

(b) Tape Measures

The standard unit of length is

(a) Centimetre (cm)

100cm – 1 metre (m)

Centi means hundredth

(b) Millimetre (mm)

1 000 mm = 1 metre (m)

Milli means thousandth

(c) Kilometre

1 000 m = 1 km

Kilo means thousand

In many parts of the world today, people use the

same unit to measure. Senzo, Themba and their friends will tell us more.

1 cm

10 mm

x 1000 sticks = 1 000 m = 1 km

Exercise:

Do the following exercises in your notebooks.

1. 1 cm = 10 mm.

Answer the following questions.

(a) Estimate the length of your pinkie.

(b) Estimate the length of your foot.

(c) Estimate the length of your arm from shoulder to wrist.

(d) Name one object in the house that is about 10 centimetre long.

(e) Name one object in the house that is about 30 centimetre long or wide.

2. What is the length of the following objects?

Write the answers in centimetre (cm) and millimetre(mm).

(a)

(b)

(c)

(d)

(e)

________ cm = __________mm

________ cm = __________mm

________ cm = __________mm

________ cm = __________mm

________ cm = __________mm

3. Here is a challenge for you.

Meet four friends: Kyle, Waldo, Thando, Nazli and Jessica.

Help them to measure their height.

(a) Write each person’s height in centimetre(cm).

Kyle’s height is _____________ cm.

Waldo’s height is ______________cm.

Thando’s height is ___________cm.

Nazli’s height is _____________ cm.

Jessica’s height is _____________cm.

(b) Who is the tallest? ____________________

(c) Who is the shortest? _____________________

(d) Waldo is _____________ cm taller than Thando.

(e) Nazli is _______________ cm shorter than Jessica.

(f) Arrange their heights from the shortest to the tallest.

Kyle Waldo Thando

o

Nazli Jessica


Do the following exercises in your notebooks.

1. 1 cm = 10 mm.

Answer the following questions:

Write your answers in centimetre (cm) and millimeter (mm)

(a) Estimate the length of your pinkie.

(Ask your Mom / granny / aunt if you estimated correctly ).

(b) Estimate the length of your foot.

(Ask your Mom / granny / aunt if you estimated correctly).

(c) Estimate the length of your arm from shoulder to wrist.

(Ask your Mom / granny / aunt if you estimated correctly)

(d) Name one object in the house that is about 10 centimetrelong.

(e) (Ask your Mom / granny / aunt if you estimated correctly)

(f) Name one object in the house that is about 30 centimetre long or wide.

(Ask your Mom / granny / aunt if you estimated correctly)

2. What is the length of the following objects?

Write the answer in centimetre (cm) and millimeter (mm).

(a)

(b)

(c)

(d)

(e)


Meet four friends: Kyle, Waldo, Thando, Nazli and Jessica.

4 cm = 40 mm

4 cm = 40 mm

3 cm = 30 mm

6 𝟏

𝟐 cm = 65 mm

5 𝟏

𝟐 cm = 55 mm

Help them to measure their height.

(a) Write each person’s height in centimetre(cm).

Kyle’s height is 130 cm.

Waldo’s height is 157cm.

Thando’s height is 145 cm.

Nazli’s height is 132 cm.

Jessica’s height is 135 cm.

(b) Who is the tallest? Waldo – 157 cm

(c) Who is the shortest? Kyle – 130 cm

(d) Waldo is 12 cm taller as Thando.

(e) Nazli is 3 cm shorter as Jessica.

(f) Arrange their heights from the shortest to the tallest.

Kyle (130 cm) ; Nazli (132 cm) ; Jessica (135 cm) ; Thando (145 cm) ; Waldo (157 cm)

Kyle Waldo Thando

o

Nazli Jessica

Day 3: Length in different units

Introduction:

There is 10 millimetre in 1 centimetre.

There is 100 centimetre in 1 metre.

There is 1000 metre in 1 kilometre.

Buddies, do you think that we can

measure everything in centimetre?

Definitely not. Today, Travis and

Imraan will tell us more.

You already know the

following.

1 cm

10 mm

100 cm

x 1000 metre sticks = 1 000 m = 1 km

Today, we are going to write:

Millimetre units as centimetre units.

Centimetre units as millimeter units.

Metre units as kilometre units.

Kilometre units as metre units.

Example: Look at the ruler below:

1. 10 mm = 1 cm. That is why

20 mm = 2 cm, and

30 mm = 3 cm.

What do you do with

5 mm?

15 mm?

25 mm?

2. 100 cm = 1m. That is why

200 cm = 2 m, and

300 cm = 3 m.

What do you do with: 50 cm?

150 cm?

250 cm?

3. 1 000 m = 1 km. That is why

2 000 m = 2 km, and

3 000 m = 3 km.

What do you do with:

500 m?

1 500 m?

2 500 m?

5 mm 15 mm 25 mm

Did you know?

5 mm = 0 cm 5mm or 𝟏

𝟐 cm

15 mm = 1 cm 5 mm or 1𝟏

𝟐 cm

25 mm = 2 cm 5 mm or 2𝟏

𝟐 cm

10 20 30

+10 +10 +10

mm 40

50 cm 150 cm 250 cm

100 cm 200 cm 300 cm

Did you know?

50 cm = 0 m 50 cm or 𝟏

𝟐 m

150 cm = 1 m 50 cm or 1𝟏

𝟐 m

250 cm = 2 m 50 cm or 2𝟏

𝟐 m

1 m 2 m 3 m

Did you know?

500 m = 0 km 500 m or 𝟏

𝟐 km

1 500 km = 1 km 500 m or 1𝟏

𝟐 km

2 500 km = 2 km 500 m or 2𝟏

𝟐 km

EXERCISE: Complete the following exercises in your notebook.

1. Write the following lengths in millimetre.

(a) 5 cm = ___ mm

(b) 6 cm = ___ mm

(c) 10 cm = ___ mm

(d) 12 cm = ___ mm

(e) 20 cm = ___ mm

2. Write the following lengths in centimetre and millimetre

(a) 41 mm = 40 mm + 1 mm = 4 cm 1 mm

(b) 16 mm = 10 mm + __ mm = __cm __mm

(c) 34 mm = ___ mm + __ mm = __ cm __mm

(d) 67 mm = ___ mm + __ mm = __ cm __mm

(e) 93 mm = ___ mm + __ mm = __ cm __ mm

3. Write the following lengths in metre.

(a) 400 cm = ____ m

(b) 500 cm = ____ m

(c) 900 cm = ____m

(d) 1 000 cm = _____ m

(e) 2 000 cm = _____ m

4. Write the following lengths in metre and centimetre.

(a) 450 cm = 400 cm + 50 cm = 4 m 50 cm

(b) 320 cm = 300 cm + 20 cm = ___ m ___ cm

(c) 576 cm = ____ cm + ___ cm = ___ m ___ cm

(d) 135 cm = ____ cm + ___ cm = ___ m ___ cm

(e) 2 345 cm= ____ cm + ___ cm = ___ m ___ cm

5. Write the following lengths in centimetre.

(a) 5 m 34 cm = 500 cm + 34 cm = 534 cm

(b) 7 m 19 cm = ____ cm + 19 cm = ____ cm

(c) 1 m 15 cm = ____ cm + __ cm = ____ cm

(d) 10 m 5 cm = ____ cm + __ cm = ____ cm

(e) 18 m 90 cm = ____ cm + __ cm = ____ cm

6. Write the following lengths in kilometre and metre. (remember: 1 000 m = 1 km)

(a) 460 m = ****** m + 460 m = 0 km 460 m

(b) 1 300 m = 1 000 m + 300 m = 1 km 300 m

(c) 765 m = ****** m + ____ m = __ km ___ m

(d) 1 249 m = _____ m + ____ m = __ km ___ m

(e) 2 014 m = _____ m + ____ m = __ km ___ m


Write the following lengths as indicated.

(a) 1𝟏

𝟐 km = 1 500 m

(b) 3 500 m = 3𝟏

𝟐 km

(c) 𝟒𝟏

𝟐 km = ______ m

(d) 8𝟏

𝟐 m = _______ cm

(e) 75 mm = ______ cm

(f) 12𝟏

𝟐 cm = ______ mm

(g) 10 500 cm = ______ m


Exercise: Complete the following exercises in your notebook.

1. Write the following lengths in millimetre.

(a) 5 cm = 50 mm

(b) 6 cm = 60 mm

(c) 10 cm = 100 mm

(d) 12 cm = 120 mm

(e) 20 cm = 200 mm

2. Write the following lengths in centimetre and millimetre

(a) 41 mm = 40 mm + 1 mm = 4 cm 1 mm

(b) 16 mm = 10 mm + 6 mm = 1 cm 6 mm

(c) 34 mm = 30 mm + 4 mm = 3 cm 4 mm

(d) 67 mm = 60 mm + 7 mm = 6 cm 7 mm

(e) 93 mm = 90 mm + 3 mm = 9 cm 3 mm

3. Write the following lengths in metre.

(a) 400 cm = 4 m

(b) 500 cm = 5 m

(c) 900 cm = 9 m

(d) 1 000 cm = 10 m

(e) 2 000 cm = 20 m

4. Write the following lengths in metre and centimetre.

(a) 450 cm = 400 cm + 50 cm = 4 m 50 cm

(b) 320 cm = 300 cm + 20 cm = 3 m 20 cm

(c) 576 cm = 500 cm + 76 cm = 5 m 76 cm

(d) 135 cm = 100 cm + 35 cm = 1 m 35 cm

(e) 2 345cm = 2 300 cm + 45 cm = 23 m 45 cm

5. Write the following lengths in centimetre.

(a) 5 m 34 cm = 500 cm + 34 cm = 534 cm

(b) 7 m 19 cm = 700 cm + 19 cm = 719 cm

(c) 1 m 15 cm = 100 cm + 15 cm = 115 cm

(d) 10 m 5 cm = 1000 cm + 5 cm = 1 005 cm

(e) 18 m 90 cm = 1 800 cm + 90 cm = 1 890 cm

6. Write the following lengths in kilometre and metre. (remember: 1 000 m = 1 km)

(a) 460 m = ***** m + 460 m = 0 km 460 m

(b) 1 300 m = 1 000 m + 300 m = 1 km 300 m

(c) 765 m = ***** m + 765 m = 0 km 765 m

(d) 1 249 m = 1 000 m + 249 m = 1 km 249 m

(e) 2 014 m = 2 000 m + 14 m = 2 km 14 m

7. Here is a challenge.

Write the following lengths as indicated.

(a) 1𝟏

𝟐 km = 1 500 m

(b) 3 500 m = 3𝟏

𝟐 km

(c) 𝟒𝟏

𝟐 km = 4 500 m

(d) 8𝟏

𝟐 m = 850 cm

(e) 75 mm = 7𝟏

𝟐 cm

(f) 12𝟏

𝟐 cm = 125 mm

(g) 10 500 cm = 10𝟏

𝟐 m

If most of your work are correctly done,

you earn a star.

Beautiful! You are so hard-working.

Day 4: Rounding Off of Lengths

Introduction

Buddies, you probably heard of rounding off. By now you know that it is estimation.

Rounding off of lengths are done in the same way as

whole numbers.

In rounding off to the nearest 10, we are working with

multiples of 10.

In rounding off to the nearest 100, we are working

with multiples of 100.

In rounding off to the nearest 1 000, we are working

with multiples of 1 000.

Example:

37cm rounded off to the nearest (multiple of) 10

How far must Franny Frog jump from 37?

The ten that we hear and see, is 30. 40 is the next 10.

Is it closer to 30 than it is to 40?

35 is in the middle of 30 and 40.

The distance from 37 to 40 is shorter.

Thus: 37 rounded off to the nearest 10 is 40.

37cm ≈ 40cm (We read it as: 37 approximately rounded off is equal to 40)

Middle

Inlei

ding

145 km rounded off to the nearest 100.

How far must Tyler drive to the nearest petrol station?

Is it closer to 100 than to 200?

150 is in the middle of 100 and 200.

145 is before 150.

145 is thus closer to 100

145km ≈ 100km (We read it as: 145 approximately rounded off is equal to

100)

145

Middle

2 630 mm ronded off to the nearest1 000.

We hear and see 2 000 in the number. 3000 is the next thousand.

We find 2 630 between 2 000 and 3 000.

Which thousand is closer to 2 630?

Find the middle between 2 000 and 3 000. It is 2 500.

We find 2 630 after 2 500.

2 630 is closer to 3 000.

Thus: 2 630 ≈ 3 000

We read it as: 2 630 approximately rounded off is equal to 3 000

Middle

2 630

Exercise: 1. Round the following numbers off to the nearest 10 (You can draw a number line to help

you)

(a) 26 cm

(b) 144 cm

(c) 93 km

(d) 533 mm

2. Round off to the nearest 100. (Think of the number on a number line)

(a) 78 cm

(b) 301 mm

(c) 549 km

(d) 4 718 m

3. Round off to the nearest 1 000. (Think of the number on a number line)

(a) 1 991 mm

(b) 6 90 km

(c) 2 500 m

(d) 4 490 cm

4. In Dubai is a lot of skyscrapers.

Round off their heights to the nearest 100

(a) (b) (c)

828 m 306m 321 m

You earned a star if

you completed all

your work.


Exercises: 1. Round the following numbers off to the nearest 10 (You can draw a number line to help

you)

(a) 26 cm 30 cm

(b)144 cm 140 cm

(c) 93 km 90 km

(d)533 mm 530 mm

1. Round off to the nearest 100. (Think of the number on a number line)

(a) 78 cm 100 cm

(b) 301 mm 300 mm

(c) 549 km 500 km

(d) 4 718 m 4 700 m

2. Round off to the nearest 1 000. (Think of the number on a number line)

(a) 1 991 mm 2 000 mm

(b) 690 km 1 000 km

(c) 2 500 m 3 000 m

(d)4 490 cm 4 000 cm

3. In Dubai is a lot of skyscrapers.

Round off their heights to the nearest 100.

(b) (b) (c)

You earned a star if you

completed all your work

Day 5: Informal Assessment

Do the informal assessment tasks.

Length

Term 2

Informal Assessment 1. Select the closest unit of measurment.

1.1 The length of the nail is:

(a) 8 m

(b) 8 cm

(c) 8 mm

1.2 The height of a chair.

(a) 100 cm

(b) 100 m

(c) 100 mm

1.3 The length of your foot.

(a) 140 mm

(b) 140 m

(c) 140 cm

1.4 The height of the classroom door.

(a) 2 450 km

(b) 2 450 mm

(c) 2 450 cm

1.5 The height of the washing poles.

(a) 160 m

(b) 160 mm

(c) 160 cm

2. The distance between Cape Town and Johannesburg

is 1 397 km.

(a) Round off the distance to the nearest 10.

(b) Round off the distance to the nearest 100.

(c) Round it off to the nearest 1 000.

3. Mrs Taylor made masks for all the Gr. 4 learners of Freckles

Primary. She calculated that she will need 935 cm of

material for 40 learners.

(a) Round off the length of the material to the nearest 10.

(b) Round off the length of the material to the nearest 100.

(c) Round off the length of the material to the nearest 1 000.

(d) How many metres of material is this?

4. During all the athletic events earlier this year, Thapelo

covered 14 500 m.


(b) Write the distance in kilometre.

Length

Term 2

Informal Assessment

Memorandum / Answers. Mark your work

1. Select the closest unit of measurment.

1.1 The length of the nail is:

(a) 8 m

(b) 8 cm

(c) 8 mm

1.2 The height of a chair.

(a) 100 cm

(b) 100 m

(c) 100 mm

1.3 The length of your foot.

(a) 140 mm

(b) 140 m

(c) 140 cm

1.4 The height of the classroom door.

(a) 2 450 km

(b) 2 450 mm

(c) 2 450 cm

1.5 The height of the washing poles.

(a) 160 m

(b) 160 mm

(c) 160 cm

2. The distance between Cape Town and Johannesburg

is 1 397 km.


1 400 km

(b) Round off the distance to the nearest 100.

1 400 km

(c) Round it off to the nearest 1 000.

1 000 km

3. Mrs Taylor made masks for all the Gr. 4 learners of Freckles

Primary. She calculated that she will need 935 cm of

material for 40 learners.

(a) Round off the length of the material to the nearest 10.

940 cm

(b) Round off the length of the material to the nearest 100.

900 cm

(c) Round off the length of the material to the nearest 1 000.

1 000 cm

(e) How many metres of material is this?

9 m 35 cm

4. During all the athletic events earlier this year, Thapelo

covered 14 500 m.


15 000 km

(b) Write the distance in kilometre.

14 km 500 m or 14𝟏

𝟐 km

Documents

MATHEMATICS GRADE 41)Te… · Thando’s height is 145 cm. Nazli’s height is 132 cm. Jessica’s height is 135 cm. (b) Who is the tallest? Waldo – 157 cm (c) Who is the shortest?