Exercise 8.1
Question 1
Answer 1:
Hundreds  Tens  Ones  Tenths 
0  3  2  31.2 
1  1  4  110.4 
Question 2
Write the following decimals in the place value table.
(a) 19.4
(b) 0.3
(c) 10.6
(d) 205.9
Answer 2:
(a)  
Hundreds  Tens  Ones  Tenths 
0  1  9  4 
(b)  
Hundreds  Tens  Ones  Tenths 
0  0  0  3 
(c)  
Hundreds  Tens  Ones  Tenths 
0  1  0  6 
(d)  
Hundreds  Tens  Ones  Tenths 
2  0  5  9 
Question 3
Write each of the following as decimals:
(a) Seventenths
(b) Two tens and ninetenths
(c) Fourteen point six
(d) One hundred and two ones
(e) Six hundred point eight
Answer 3:
(a) seventenths = 7/10 = 0.7
(b) 2 tens and 9tenths
(c) Fourteen point six = 14.6
(d) One hundred and 2ones = 100 + 2 x 1 = 100 + 2 = 102
(e) Six hundred point eight = 600.8
Question 4
Write each of the following as decimals:
(a) 5/10
(e) 88/10
(g) 3/2
(h) 2/5
(i) 12/5
Answer 4:
= 8 + 0.8 = 8.8
Question 5
Write the following decimals as fractions. Reduce the fractions to lowest terms.
(a) 0.6
(b) 2.5
(c) 1.0
(d) 3.8
(e) 13.7
(f) 21.2
(g) 6.4
Answer 5:
Question 6
Express the following as cm using decimals.
(a) 2 mm
(b) 30 mm
(c) 116 mm
(d) 4 cm 2 mm
(e) 162 mm
(f) 83 mm
Answer 6:
Question 7:
Between which two whole numbers on the number line are the given lie? Which of these whole numbers is nearer the number?
(a) 0.8
(b) 5.1
(c) 2.6
(d) 6.4
(e) 9.1
(f) 4.9
Answer 7:
(a) From 0 to 1, 0.8 is nearest to 1.
(b) From 5 to 6, 5.1 is nearest to 5.
(c) From 2 to 3, 2.6 is nearest to 3.
(d) From 6 to 7, 6.4 is nearest to 6.
(e) From 9 to 10, 9.1 is nearest to 9.
(f) From 4 to 5, 4.9 is nearest to 5.
Question 8: Show the following numbers on the number line:
(a) 0.2
(b) 1.9
(c) 1.1
(d) 2.5
Answer 8:
Question 9:
Write the decimal number represented by the points A, B, C, D on the given number line.
Answer 9:
Question 10:
(a) The length of Ramesh’s notebook is 9 cm and 5 mm. What will be its length in cm?
(b) The length of a young gram plant is 65 mm. Express its length in cm.
Answer 10:
Exercise 8.2
Question 1:
Complete the table with the help of these boxes and use decimals to write the number.
 Ones  Tenths  Hundredths  Numbers 
(a)         
(b)         
(c)         
Answer 1:
 Ones  Tenths  Hundredths  Numbers 
(a)  0  2  6  0.26 
(b)  1  3  8  1.38 
(c)  1  2  8  1.28 
Question 2
Write the numbers given in the following place value table in decimal form.
 Hundreds 100  Tens 10  Ones 1  Tenths 1/10  Hundredths 1/100  Thousandths 1/1000 
(a)  0  0  3  2  5  0 
(b)  1  0  2  6  3  0 
(c)  0  3  0  0  2  5 
(d)  2  1  1  9  0  2 
(e)  0  1  2  2  4  1 
Answer 2:
(a)
= 0 + 0 + 3 + 0.2 + 0.05 + 0 = 3.25
(b) 1 x 100 + 0 x 10 + 2 x 1 + 6 x (1/10) + 3 x 1/100 + 0 x (1/1000)
= 1 + 0 + 2 + 0.6 + 0.03 + 0 = 102.63
(c) 0 x 100 + 3 x 10 + 0 x 1 + 0 x (1/10) + 2 x 1/100 + 5 x (1/1000)
= 0 + 30 + 0 + 0 + 0.02 + 0.005 = 30.025
(d) 2 x 100 + 1 x 10 + 1 x 1 + 9 x 1/10 + 0 x 1/100 + 2 x (1/1000)
= 200 + 10 + 1 + 0.9 + 0 + 0.002 = 211.902
(e) 0 x 100 + 1 x 10 + 2 x 1 + 2 x 1/10 + 4 x 1/100 + 1 x (1/1000)
= 0 + 10 + 2 + 0.2 + 0.04 + 0.001 = 12.241
Question 3: Write the following decimals in the place value table:
(a) 0.29
(b) 2.08
(c) 19.60
(d) 148.32
(e) 200.812
Answer 3:
 Numbers  Hundreds  Tens  Ones  Tenths  Hundredths  Thousandths 

 100  10  1  1/10  1/100  1/1000 
(a)  0.29  0  0  0  2  9  0 
(b)  2.08  0  0  2  0  8  0 
(c)  19.60  0  1  9  6  0  0 
(d)  148.32  1  4  8  3  2  0 
(e)  200.812  2  0  0  8  1  2 
Question 4: Write each of the following as decimals:
(a)
(b) 137 + (5/100)
(c)
(d)
(e)
Answer 4:
(a) 20 + 9 + 0.4 + 0.01 = 29.41
(b) 137 + 0.05 = 137.05
(c) 0.7 + 0.06 + 0.004 = 0.764
(d) 23 + 0.2 + 0.006 = 23.206
(e) 700 + 20 + 5 + 0.09 = 725.09
Question 5: Write each of the following decimals in words:
(a) 0.03
(b) 1.20
(c) 108.56
(d) 10.07
(e) 0.032
(f) 5.008
Answer 5:
(a) Zero point zero three
(b) One point two zero
(c) One hundred and eight point five six
(d) Ten point zero seven
(e) Zero point zero three two
(f) Five point zero zero eight
Question 6: Between which two numbers in tenths place on the number line does each of the given number lie?
(a) 0.06
(b) 0.45
(c) 0.19
(d) 0.66
(e) 0.92
(f) 0.57
Answer 6: All the numbers lie between 0 and 1.
(a) 0.06 is nearer to 0.1.
(b) 0.45 is nearer to 0.5.
(c) 0.19 is nearer to 0.2.
(d) 0.66 is nearer to 0.7.
(e) 0.92 is nearer to 0.9.
(f) 0.57 is nearer to 0.6.
Question 7: Write as fractions in lowest terms:
(a) 0.60
(b) 0.05
(c) 0.75
(d) 0.18
(e) 0.25
(f) 0.125
(g) 0.066
Answer 7: