TOP Maths Textbook 1A

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t Chap

1

er

Numbers from 0 to 20

four, five. , e e r h t , o w One, t ive. Once I caught a fish al

, ten. Six, seven, eight, nine Then I let it go again!

I will learn to: • Count, read and write numbers to 20 • Say numbers in order — forward from 1 to 100; backward from 20 to 0

Do you know of any other number rhymes? What number can you count up to?

• Know the value of a digit in a two-digit number • Use the ‘=’ sign • Give an estimate of up to 30 objects


Numbers to 10

Let us count from 1 to 10.

1

one

2

two

3

three

4

four

5

five

We can write a number as a numeral or as a word. 5  five numeral

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word


Chap

6

six

7

seven

8

eight

9

nine

10

ten

Numbers from 0 to 20

ter

1

3


How many legs do these animals have? 1

5

2

6 3 4

8

7

spider

snake

The spider has 8 (eight) legs. The snake has no legs. We say that it has 0 legs. We can write 0 in words as zero.

Try This!

Count the pictures. How many are there? Write the number in numerals and in words.

and

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Hands-On Maths Matching pairs Get into pairs.

Chap

Materials needed (per pair):

ter

1

cards with numbers 1 to 10 in numerals •c ards with numbers 1 to 10 in words •

1 Mix up one set of cards and place them face down in a row. Do the same for the other set of cards. Put them in a different row.

2 One player picks a card from each row. Keep both cards if they are a matching pair. Return the cards to the rows if they are not a matching pair.

3 Take turns to pick the cards. Repeat step 2. The player with more cards at the end of the game wins.

Numbers from 0 to 20

5


On Your Own

1 Count. How many are there?

(a)

(b)

2 Write these numbers in numerals.

(a) five

(b) seven

(c) ten

3 Write these numbers in words.

(a) 3

(b) 8

(c) 0

4 How many children are wearing glasses?

Write the number in numerals.

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Chap

ter

1

Numbers to 20 How many are there?

First, we make 10. Then we count on.

1

3

2

4

5

11 eleven 6

8

7

9

10

10 We can write 11 in words as eleven. Look at the following. Can you count these?

11   12 twelve

10

Ano Fasc th inating Fact! doze er wor d n old F . The w for the num renc ber 12 is a o h w rd dozen c omes from an ord that m eans a group of 12. Numbers from 0 to 20

7


11 12 13 thirteen 10

11 12 13 14 fourteen 10

11 12 13 14 15 fifteen 10

11 12 13 14 15

10 8

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16  sixteen


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ter

1

11 12 13 14 15

10

16

17 seventeen

11 12 13 14 15

10

16 17 18 eighteen

11 12 13 14 15 10

16 17 18 19 nineteen

11 12 13 14 15 10

16 17 18 19 20  twenty Numbers from 0 to 20

9


How many cubes ( 

 ) are there?

First, I make 10. 10 and 5 make 15.

10 There are 15 (fifteen) cubes. Try This!

How many books are there? Write in numerals and in words.

10 and

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Chap

ter

1

Hands-On Maths Forward and backward Get into pairs. Part of a number grid showing the numbers 1 to 100 has been torn away. Look at the grid and read the numbers 1 to 20 out loud.

1, 2, 3, ‌

Now continue counting on to 100 by following the steps below.

1 Start by counting from 21 to 30. 2 Then get your friend to continue and count the next ten numbers. 3 Take turns to continue counting on ten numbers at a time. Are you able to count up to 100? If not, what numbers can both of you count up to? Now, try counting back from 20 to 0. You may use the number grid shown to help you.

Numbers from 0 to 20

11


On Your Own

1 How many are there?

(a)

10

(b) (c)

2 Write these numbers in numerals.

(a) twelve

(b) eighteen

3 Write these numbers in words.

(a) 13

(b)  15

(c) 17

(d)  19

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TOP Maths Stage 1

(c) twenty


Chap

ter

1

4 Fill in the boxes.

(a) 10 and 3 make

. (b) 10 and 4 make

(c) 10 and 7 make

. (d) 10 and

.

make 20.

5 Look at the picture shown. Count the animals and write

the correct numbers in the boxes below.

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Numbers from 0 to 20

13


Place value — Tens and units Ari wants to count the number of cubes he has.

He uses a place value table to help him count.

10 10 units make 1 ten.

1 ten 6 units is equal to 16. We can write ‘is equal to’ as ‘=’. So, 1 ten 6 units = 16.

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Tens

Units

1

6


Chap

ter

1

(1) 10 units make 1 ten.

10 (2) Numbers with tens and units are called two-digit numbers. In a two-digit number, the first digit tells us the number of tens and the second digit tells us the number of units. THINK!

How many tens and units are there in the number 9? Try This!

Fill in the boxes below. Tens

Units

ten

units =

Numbers from 0 to 20

15


On Your Own

1 Write the missing numbers.

(a) Tens

Units

ten

(b)  Tens

units =

Units

ten

units =

2 Fill in the boxes.

(a) 12 = 1 ten

(c)

units

(b) 17 =

= 1 ten 9 units

(d)

ten 7 units = 2 tens 0 units

3 Which of these show the number 13? Tick (3) the correct

boxes.

its

1 ten 3 un

3 units

13 units

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Chap

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1

Estimation

Without counting, can you estimate or guess how many marbles there are?

Now, try looking at how much space a group of 10 marbles occupy. Then guess how many groups of 10 there are.

There are about 2 more groups of 10.

So, there are about 3 groups of 10, or 30 marbles altogether. When we estimate the number of objects, we are making a reasonable guess about how many objects there are.

Numbers from 0 to 20

17


How can I check my estimate? How do I know if it is a good estimate or not? To check your estimate, count the marbles to find the actual number.

There are actually 29 marbles.

Then use a number track to compare your estimate and the actual number of marbles to see if they are close to each other.

20

21

22

23

24

25

26

27

28

29

30

actual estimate

29 is very close to 30. It is closer to 30 than to 20. So, we can say that our estimate of about 30 marbles is a good estimate.

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Chap

On Your Own

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1 Estimate. Then count to find the actual number.

Estimate:   Actual count: 2 The picture below shows some ribbons. Tina estimates that there are about 20 ribbons. Simon estimates that there are about 30 ribbons.

(a) How many ribbons are there actually?

(b) Whose estimate is better? Workbook

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Numbers from 0 to 20

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I Know That...

• I can write a number as a numeral or as a word. (page 2) Example: 5  five

numeral

word

• When there are more than 10 things, I first make 10. Then I count on from 10. (page 7) Example:

First, make 10. 10 and 5 make 15.

10 • 10 units make 1 ten. (page 14)

10

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Chap

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1

• I can also use a place value table to help me count. (page 14)

Tens

Units

1

2

1 ten 2 units = 12

• Numbers with tens and units are called two-digit numbers. In a two-digit number, the first digit tells us the number of tens and the second digit tells us the number of units. (page 15) Example: 13

tens  units

• When I estimate the number of objects, I am making a reasonable guess about how many objects there are. (page 17)

30

Numbers from 0 to 20

21


I Know That...

• I can use a number track to compare my estimate and the actual number of objects. (page 18) • A good estimate is one which is near to the actual answer. (page 18) Workbook

1A

Know these words Read these words aloud and check if you know what they mean. • Numeral • Place value • Count on • Units • Tens • Equal • Digit • Estimate

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Go to Putting

It Together

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Chap

21

st

1

ry Skills ntu Ce

tiv rea ity C

ter

K n ow Apply What You

1. Look at this alien. How many of the parts below does it have? (a) ears (b) eyes (c) legs (d) horns

In the space below, use your imagination to draw an alien that has 4 ears, 5 eyes, 7 legs and 9 horns.

Numbers from 0 to 20

23


Co m

nica t

n io

mu

g in

C &P r r

g

l Think i ica it lem-Sol n b v o

2. A shop sells pens in packets of ten or separately.

Dan needs to buy exactly 17 pens.

How many packets of pens should he buy?

How many extra pens should he buy?

What is a quick way of working out the answer without counting?

3. Farmer Jones has some chickens and ducks. Each of these animals has 2 legs.

There are 20 legs altogether. He has 4 ducks. How many chickens does Farmer Jones have? Hint: Draw pictures to help you.

Workbook

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Go to Putting

It Together

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