Samacheer Kalvi 7th Maths Solutions Term 2 Chapter 1 Number System Intext Questions

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Tamilnadu Samacheer Kalvi 7th Maths Solutions Term 2 Chapter 1 Number System Intext Questions

Exercise 1.1
(Try These Text book Page No. 2)

Question 1.
Observe the following and write the fraction of the shaded portion and mention in decimal form also.

Solution:
(i) Total parts = 8
Shaded parts = 4

(ii)

(iii)

Question 2.
Represent the following fractions in decimal form by converting denominator into ten or powers of 10.

Solution:

Question 3.
Give any two life situations where we use decimal numbers.
Solution:
(i) Measuring weight of gold.
(ii) Weighing our height

(Try These Text book Page No. 3)

Question 1.
Represent the following decimal numbers pictorially.
(i) 5 ones and 3 tenths
(ii) 6 tenths
(iii) 7 ones and 9 tenths
(iv) 6 ones and 4 tenths
(v) Seven tenths
Solution:
(i) 5 ones and 3 tenths

(ii) 6 tenths

(iii) 7 ones and 9 tenths

(iv) 6 ones and 4 tenths

(v) Seven tenths

(Try These Text book Page No. 5 & 6)

Question 1.
Express the following decimal numbers in an expanded form and place value grid form.
(i) 56.78
(ii) 123.32
(iii) 354.56
Solution:
(i) 56.78
(a) Expanded form
56.78 = 5 × 10¹ + 6 × 10⁰ + 7 × 10^-1 + 8 × 10^-2

(b) Place value grid

(ii) 123.32
(a) Expanded form
123.32 = 1 × 10² + 2 × 10¹ + 3 × 10⁰ + 3 × 10^-1 +2 × 10^-2

(b) Place value grid

(iii) 354.56
(a) Expande form
354.56 = 3 × 10² + 5 × 10¹ + 4 × 10⁰+ 5 × 10^-1 + 6 × 10^-2

(b) Place value grid

Question 2.
Express the following measurements in terms of metre and in decimal form. One is done for you.

Solution:

Question 3.
Write the following numbers in the place value grid and find the place value of the underlined digits.
(i) 36.37
(ii) 267.06
(iii) 0.23
(iv) 27.69
(v) 53.27
Solution:

(i) Place value of 3 in 36.37 is Tenths.
(ii) Place value of 6 in 267.06 is Hundredths.
(iii) Place value of 2 in 0.23 is Tenths.
(iv) Place value of 9 in 27.69 is Hundredths.
(v) Place value of 2 in 53.27 is Tenths.

Exercise 1.2

(Try These Text book Page No. 10)

Question 1.
Convert the following fractions into the decimal numbers.
(i) \(\frac { 16 }{ 1000 } \)
(ii) \(\frac { 638 }{ 10 } \)
(iii) \(\frac { 1 }{ 20 } \)
(iv) \(\frac { 3 }{ 50 } \)
Solution:
(i) \(\frac { 16 }{ 1000 } \) = 0.016
(ii) \(\frac { 638 }{ 10 } \) = 63.8
(iii) \(\frac { 1 }{ 20 } \) = \(\frac{1 \times 5}{20 \times 5}\) = \(\frac { 5 }{ 100 } \) = 0.05
(iv) \(\frac { 3 }{ 50 } \) = \(\frac{3 \times 2}{50 \times 2}\) = \(\frac { 6 }{ 100 } \) = 0.06

Question 2.
Write the fraction for each of the following:
(i) 6 hundreds + 3 tens + 3 ones + 6 hundredths + 3 thousandths.
(ii) 3 thousands + 3 hundreds + 4 tens + 9 ones + 6 tenths.
Solution:
(i) 6 hundreds + 3 tens + 3 ones + 6 hundreds + 3 thousandths.
= 6 × 100 + 3 × 10 + 3 × 1 + 0 × \(\frac { 1 }{ 10 } \) + 6 × \(\frac { 1 }{ 100 } \) + 3 × \(\frac { 1 }{ 1000 } \)
= 600 + 30 + 3 + 0 + \(\frac { 6 }{ 100 } \) + \(\frac { 3 }{ 1000 } \)
= 633 + 0.06 + 0.003
= 633.063

(ii) 3 thousands + 3 hundreds + 4 tens + 9 ones + 6 tenths.
= 3 × 1000 + 3 × 100 + 4 × 10 + 9 × 1 + 6 × \(\frac { 1 }{ 10 } \)
= 3000 + 300 + 40 + 9 + \(\frac { 6 }{ 10 } \)
= 3349 + 0.6
= 3349.6

Question 3.
Convert the following decimals into fractions.
(i) 0.0005
(ii) 6.24
Solution:
(i) 0.0005 = \(\frac { 5 }{ 10000 } \) = \(\frac{5 \div 5}{10000 \div 5}\) = \(\frac { 1 }{ 2000 } \)
(ii) 6.24 = \(\frac { 624 }{ 100 } \) = \(\frac{624 \div 4}{100 \div 4}\) = \(\frac { 156 }{ 25 } \)

Exercise 1.4

(Try These Text book Page No. 22)

Question 1.
Mark the following decimal numbers on the number line.
(i) 0.3
(ii) 1.7
(iii) 2.3
Solution:
(i) 0.3
We know that 0.3 is more than 0, but less than 1.
There are 3 tenths in it. Divide the unit lenght between O and 1 on the number line
into 10 equal parts and take 3 parts, which represent 0.3.

(ii) 1.7
We know that 1.7 is more than 1, but less than 2.
There are one ones and 7 tenths in it. Divide the unit length between 1 and 2 on the number line into 10 equal parts and take 7 parts which represents 1.7 = 1 + 0.7

(iii) We know that 2.3 is more than 2 and less than 3.
There are 2 ones and 3 tenths in it. Divide the unit length between 2 and 3 into 10 equal parts and take 3 parts, which represents 2.3 = 2 + 0.3

Question 2.
Identify any two decimal numbers between 2 and 3.
Solution:
2.5 and 2.9

Question 3.
Write any decimal number which is greater than 1 and less than 2.
Solution:
1.7, 1.9, 1.6, ………………..