WMPB14034B
Special Features
3 Topical-based practices 3 Revision papers 3 Challenging questions 3 Complete answers
Mastering Mathematics Workbook 4B
Mastering Mathematics is a comprehensive series of assessment workbooks which is written based on the latest Primary Mathematics Syllabus issued by the Ministry of Education of Singapore. Each of the workbooks provides sufficient practices on various types of questions. The approach adopted by the writers aims at reinforcing mastery of mathematical concepts, improving problem-solving skills and developing creative and critical thinking skills.
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Primary
Published by:
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Pelangi Publishing Singapore Pte. Ltd.
In collaboration with:
Dickens Publishing Ltd. Suite G7-G8, Davina House, 137-149 Goswell Road, London, EC1V 7ET, United Kingdom. E-mail: info@dickenspublishing.co.uk
( 201112597 C )
WMPB14034B
ISBN: 978-981-07-1231-0
,!7IJ8B0-hbcdba!
In collaboration with Dickens Publishing Ltd. (UK) PELANGI
Lilian Yeo
Unit 9
Decimals (Part 1) ................................................. 1
Unit 10
Decimals (Part 2) ...............................................17
General Revision 1 ......................................................... 24 Unit 11
Time ............................................................. 30
Unit 12
Area and Perimeter ........................................... 38
General Revision 2.......................................................... 48 Unit 13
Symmetry ....................................................... 55
Unit 14
Tessellations .................................................... 59
General Revision 3 ......................................................... 66 Final Revision ............................................................... 74 Challenging Questions .................................................... 84 Answers .................................................................... 87
iv
00 Content 4B.indd 4
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Mathematics Primary 4B Unit 9 Decimals (Part 1)
9
Decimals (Part 1)
A Count the shaded parts. Complete the table below. Figure
Fraction
Decimal
Read as …
1. 10 2. 10 3. 10 4. 10 5.
6.
1
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Mathematics Primary 4B Unit 9 Decimals (Part 1)
B Complete the place values. Hundreds
Tens
Ones
Tenths
0.3
·
2.3
·
42.3
·
542.3
·
217.6
·
C Write each fraction as a decimal. 7 = 10 =
1.
3. 9 = 10 =
+
tenths
ones +
tenths
4.
7. 37 = 10 = =
3 = 10 =
tenths
one +
tenths
2.
5. 1 2 = 10 =
4 = 10 =
tenths
tenths
6. 8 5 = 10 =
8. 53 = 10 =
ones +
tenths
+ ones +
tenths
=
2
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Mathematics Primary 4B  Unit 9 Decimals (Part 1)
D Write each decimal in tenths. (1 whole = 10 tenths). 1. 0.8 =
tenths
2. 0.5 =
tenths
3. 0.2 =
tenths
4. 0.4 =
tenths
5. 5.1 =
tenths
6. 8.3 =
tenths
7. 12.9 =
tenths
8. 65.4 =
tenths
E Write a decimal for each of the following. 1. 3 tenths =
2. 8 tenths =
3. 9 tenths =
4. 5 ones 6 tenths =
5. 8 ones 4 tenths =
6. 9 ones 2 tenths =
7. 11 ones 1 tenth =
8. 48 ones 5 tenths =
F Write the missing decimal in each box. 1. 0
1
2
3
12
13
14
15
47
48
49
50
2.
3.
3
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Mathematics Primary 4B Unit 9 Decimals (Part 1)
G Fill in the blanks with the correct answers. 1. 0.5 =
tenths = 0.5 = 5 10
2. 9.4 =
ones
3. 35.6 =
= 30 + 5 +
4. 82.7 =
tens
tens
= 80 + 2 +
tenths =
+ 0.4 =
ones
+
tenths
= 30 + 5 + ones
tenths
= 80 + 2 +
5. In 24.8, (a) the digit
is in the tens place.
(b) the digit
is in the tenths place.
(c) the digit 4 stands for
ones.
(d) the value of the digit 2 is
.
(e) the value of the digit 8 is
.
(f) the value of the digit 4 is
.
6. In 85.7, (a) the digit 5 is in the
place.
(b) the digit 8 is in the
place.
(c) the digit 7 stands for
.
(d) the value of the digit 7 is
.
(e) the value of the digit 5 is
.
(f) the value of the digit 8 is
.
4
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Mathematics Primary 4B Unit 9 Decimals (Part 1)
H Count the shaded parts. Complete the table below. Figure
Fraction
Decimal
Read as …
1.
2.
3.
4.
5.
5
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Mathematics Primary 4B Unit 9 Decimals (Part 1)
I Complete the place values. Tens
Ones
Tenths
Hundredths
0.02
·
2
0.08
·
8
0.45
·
4
5
1
·
2
6
7
·
8
9
1.26 67.89
6
J Write each fraction as a decimal. 5 = 100 =
hundredths
1 = 100 =
hundredths
6 = 100 =
hundredths
12 = 100 =
tenths
hundredths
23 = 100 =
tenths
hundredths
1.
2.
3.
4.
5. 6
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Mathematics Primary 4B Unit 9 Decimals (Part 1)
6. 4 9 = 100 =
ones
hundredths
7. 3 49 = 100 =
ones
tenths
8. 24 85 = 100 =
tens
ones
hundredths
tenths
hundredths
K Write a decimal for each of the following. 1. 2 hundredths =
2. 17 hundredths =
3. 81 hundredths =
4. 100 hundredths =
5. 435 hundredths =
6. 590 hundredths =
L Write each decimal in hundredths. ( 1 whole = 10 tenths = 100 hundredths, 1 tenths = 10 hundredths) 1. 0.09 =
hundredths
2. 0.23 =
hundredths
3. 0.50 =
hundredths
4. 1.24 =
hundredths
5. 23.65 =
hundredths
6. 86.05 =
hundredths
7
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Mathematics Primary 4B  Unit 9 Decimals (Part 1)
M Write the missing decimal in each box. 1. 0
0.1
0.2
0.3
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
2.
3.
N Fill in each blank with the correct answer. 1. 0.04 =
hundredths =
4 1 00
2. 0.52 =
tenths
hundredths
= 0.5 + 0.02
=
3. 9.35 =
+ ones
=9+
+
=9+
+
4. 72.83 =
tenths
tens
ones
= 70 + 2 +
+
= 70 + 2 +
+
hundredths
tenths
hundredths
8
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Mathematics Primary 4B Unit 9 Decimals (Part 1)
5. In 36.28, (a) the digit
is in the tenths place.
(b) the digit 8 stands for
.
(c) the value of the digit 3 is
.
(d) the value of the digit 8 is
.
6. In 75.49, (a) the digit 4 is in the
place.
(b) the digit 9 is in the
place.
(c) the value of the digit 7 is
.
(d) the digit 5 stands for
.
O Complete the place values. Tens
Ones
Tenths
0.002
·
0.087
·
0.536
·
7.145
·
Hundredths Thousandths
P Write each fraction as a decimal. 1.
3 m= 1000
m
2.
57 g = 1 000
3. 763 ml = 1000
ml
4. 1145 km = 1 000
5. 6 58 m = 1000
m
6. 4 234 km = 1 000
g km km 9
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Mathematics Primary 4B  Unit 9 Decimals (Part 1)
Q Write a decimal for each of the following. 1. 8 thousandths =
2. 23 thousandths =
3. 365 thousandths =
4. 9308 thousandths =
R Fill in the missing fraction in each box. 1. 0.419 = 4 + 1 + 10 1 00
2. 3.245 = 3 + 2 + 4 + 10 1 00
3. 56.703 = 56 + 7 + 10
4. 73.296 = 73 + 2 + 9 + 10 1 00
S Write the missing decimal in each box. 1.
0
0.005
0.01
0.015
0.02
0.03
3
3.005
3.01
3.015
3.02
3.025
3.03
27
27.005
27.01
27.02
27.025
27.03
2.
3. 27.015
10
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Mathematics Primary 4B  Unit 9 Decimals (Part 1)
T Write the place value and the digit value of underlined digit as a decimal for each of the following. 1. 0.8
2. 1.27
Place value:
Place value:
Digit value:
Digit value:
3. 2.053
4. 4.196
Place value:
Place value:
Digit value:
Digit value:
5. 61.143
6. 872.342
Place value:
Place value:
Digit value:
Digit value:
U Express each decimal as a fraction or mixed number in its simplest form. 1. 3.279 =
=
=
ones thousandths +
tenths +
2. 23.816 =
tens
thousandths
=
+
=
+
ones
+
hundredths
tenths
+
hundredth
+
11
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Mathematics Primary 4B Unit 9 Decimals (Part 1)
3. 61.045 =
tens
one
thousandths
=
+
=
+
4. 278.394 =
hundreds
hundredths
=
5. 703.598 =
hundreds
hundredths
=
tenths
+
hundredths
+
tens
ones
tenths
thousandths
tens
ones
tenths
thousandths
V Fill in each blank with the correct answer. 1. In 5.982, (a) the digit
is in the thousandths place.
(b) the digit
is in the tenths place.
(c) the value of the digit 2 is
.
(d) the value of the digit 8 is
.
2. In 39.421, (a) the digit
is in the thousandths place.
(b) the digit
is in the hundredths place.
(c) the value of the digit 1 is
.
(d) the value of the digit 4 is
.
12
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Mathematics Primary 4B Unit 9 Decimals (Part 1)
3. (a) 0.7 more than 18.9 is
.
(b) 0.5 less than 72.4 is
.
(c) 0.03 more than 43.15 is
.
(d) 0.04 less than 50.7 is
.
(e) 0.006 more than 35.735 is
.
(f) 0.008 less than 65.217 is
.
4. Complete the number patterns. (a) 5.7, 5.9,
,
(b) 14.52, 14.32, (c) 23.419, (d) 43.21,
, 6.5, ,
, 13.72,
, 23.421, 23.422, , 43.31, 43.36,
,
,
W Do the following. 1. Circle the greatest number. (a) 0.08 , 0.006 , 0.008 , 0.06 (b) 47.2 , 47.02 , 42.7 , 42.07 (c) 3.28 , 3.82 , 3.802 , 3.208 (d) 3 71 , 731 , 7 31 , 7 31 1 00 1 000 1 00 1 000 2. Circle the smallest number. (a) 0.005 , 0.009 , 0.05 , 0.09 (b) 37.1 , 31.7 , 37.01 , 31.07 (c) 4.506 , 4.605 , 5.64 , 4.56 (d) 9 4 , 9 4 , 940 , 9 40 1 000 1 00 1 000 1 00 13
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Mathematics Primary 4B Unit 9 Decimals (Part 1)
3. Arrange the decimals in ascending order. (a)
0.08
0.008
0.005
0.05
(b)
2.704
2.74
2.407
2.074
(c)
9.712
9.721
9.127
9.172
4. Arrange the decimals in descending order. (a)
9.01
1.09
9.10
1.90
(b)
8.436
8.346
8.463
8.643
(c)
13.704
13.407
13.74
13.47
14
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Mathematics Primary 4B Unit 9 Decimals (Part 1)
X Do these. 1. Round off each number to the nearest whole number. (a) 8.25 ≈
(b) 26.82 ≈
(c) 0.51 ≈
(d) 17.648 ≈
2. Round off each number to 1 decimal place. (a) 12.35 ≈
(b) 48.31 ≈
(c) 39.085 ≈
(d) 62.439 ≈
3. Round off each number to the nearest tenth. (a) 7.35 ≈
(b) 56.708 ≈
(c) 84.072 ≈
(d) 70.555 ≈
4. Round off each number to 2 decimal places. (a) 6.485 ≈
(b) 12.264 ≈
(c) 83.496 ≈
(d) 51.073 ≈
5. Round off each number to the nearest hundredth. (a) 26.308 ≈
(b) 70.005 ≈
(c) 61.564 ≈
(d) 24.995 ≈
15
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