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

Additional Questions and Answers

Exercise 1.1

Question 1.
Express as rupees using decimals.
(i) 4 paise
(ii) 4 rupees 4 paise
(iii) 44 rupees 44 paise
(iv) 50 paise
(v) 625 paise
Solution:
We know that 100 paise = ₹ 1
1 paise = ₹ \(\frac { 1 }{ 100 } \)
(i) 4 paise = ₹ 4 × \(\frac { 1 }{ 100 } \) = ₹ \(\frac { 4 }{ 100 } \) = ₹ 0.04
(ii) 4 rupees 4 paise = ₹ 4 + ₹ 0.04 = ₹ 4.04
(iii) 44 rupees 4 paise = ₹ 44 + 44 paise = ₹ 44 + ₹ \(\frac { 44 }{ 100 } \) = ₹ 44 + ₹ 0.44 = ₹ 44.44
(iv) 625 paise = 600 paise + 25 paise = ₹ 6 + ₹ \(\frac { 25 }{ 100 } \) = ₹ 6 + ₹ 0.25 = ₹ 6.25

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

Question 2.
Express 7 cm in metre and kilometer.
Solution:
7 cm = \(\frac { 7 }{ 100 } \) m = 0.07 m
7 cm = \(\frac { 7 }{ 10000 } \) km = 0.00007 km

Question 3.
Write the following decimal numbers in the expanded form.
(i) 30.04
(ii) 3.04
(iii) 300.04
Solution:
(i) 30.04 = 3 × 10 + 0 × 1 + 0 × \(\frac { 1 }{ 10 } \) + 4 × \(\frac { 1 }{ 100 } \) = 3 × 10 + \(\frac { 4 }{ 100 } \)
(ii) 3.04 = 3 × 1 + 0 × \(\frac { 1 }{ 10 } \) + 4 × \(\frac { 1 }{ 100 } \) = 3 × 1 + \(\frac { 4 }{ 100 } \)
(iii) 300.04 = 3 × 100 + 0 × 10 + 0 × 1 + 0 × \(\frac { 1 }{ 10 } \) + 4 × \(\frac { 1 }{ 100 } \) = 3 × 100 + \(\frac { 4 }{ 100 } \) = 3 × 100 + \(\frac { 4 }{ 100 } \)

Question 4.
Write the place value of 2 in the following decimal numbers.
(i) 2.47
(ii) 26.89
(iii) 36.28
Solution:
(i) 2.47 Place value of 2 in 2.47 is ones.
(ii) 26.89 Place value of 2 in 26.89 is Tens.
(iii) 36.28 Place value of 2 in 36.28 is tenths

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

Exercise 1.2

Question 1.
Explain the following as fractions.
(i) Ajar containing 3.6 litres of milk.
(ii) A cup containing 9.63 mg of medicine.
Solution:
(i) 3.6 = 3 + \(\frac { 6 }{ 10 } \) = 3 + \(\frac { 3 }{ 5 } \) = 3 \(\frac { 3 }{ 5 } \) litre of milk
(ii) 9.63 = 9 + \(\frac { 6 }{ 10 } \) + \(\frac { 3 }{ 100 } \) = \(\frac { 900+60+3 }{ 100 } \) = \(\frac { 963 }{ 100 } \) mg of medicine

Question 2.
Convert into decimal.
(i) Three hundred three and nine hundredths.
(ii) Six and fifty five thousands
Solution:
(i) Three hundred three and nine hundredths
= 303 + \(\frac { 9 }{ 100 } \) = 303 + 0 × \(\frac { 1 }{ 10 } \) + 9 × \(\frac { 1 }{ 100 } \) = 303.09

(ii) Six and fifty five thousands
6 + \(\frac { 55 }{ 100 } \) = 6 + \(\frac { 5 }{ 100 } \) + \(\frac { 5 }{ 1000 } \) = 6 + \(\frac { 0 }{ 10 } \) + \(\frac { 5 }{ 100 } \) + \(\frac { 5 }{ 1000 } \) = 6.055

Question 3.
Find the decimal form of (i) 194 + 20 + 3 + \(\frac { 7 }{ 10 } \) + \(\frac { 2 }{ 100 } \)
(ii) 111 + 11 + 1 + \(\frac { 1 }{ 10 } \) + \(\frac { 1 }{ 1000 } \)
Solution:
(i) 194 + 20 + 3 + \(\frac { 7 }{ 10 } \) + \(\frac { 2 }{ 100 } \) = 217 + 7 × \(\frac { 1 }{ 10 } \) + 2 × \(\frac { 1 }{ 100 } \) = 217.72

(ii) 111 + 11 + 1 + \(\frac { 1 }{ 10 } \) + \(\frac { 1 }{ 1000 } \) = 123 + 1 × \(\frac { 1 }{ 10 } \) + 0 × \(\frac { 1 }{ 100 } \) + 1 × \(\frac { 1 }{ 1000 } \) = 123.101

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

Exercise 1.3

Question 1.
Maya bought 5 kg 300 g bananas and 3 kg 250 kg oranges. Diya bought 4 kg 800 g apples and 4 kg 150 g of mangoes. Who bought more fruits.
Solution:
Total fruits bought by Maya = 5 kg 300 g + 3 kg 250 g = 8 kg 550 g = 8.550 kg
Total fruits Diya bought = 4 kg 800 g + 4 kg 150 g = 8 kg 950 g = 8.950 kg
Comparing the whole number parts, they are equal.
Comparing thet tenths place we get 9 > 5.
∴ 8.950 kg > 8.550 kg
∴ Diya bought more fruits.

Question 2.
Which is greater 28 km or 42.6 km.
Solution:
Comparing the whole number part 42 > 28.
42.6 km is greater than 28 km.

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

Exercise 1.4

Question 1.
Show that the following numbers in a number line.
(i) 0.2
(ii) 1.8
(iii) 1.1
(iv) 2.6
Solution:
Samacheer Kalvi 7th Maths Solutions Term 2 Chapter 1 Number System Additional Questions 1

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

Question 2.
Write the decimal numbers represented by the points A, B, C, D, E and F.
Solution:
Samacheer Kalvi 7th Maths Solutions Term 2 Chapter 1 Number System Additional Questions 2
A (0.5); B (1.2); C (2.3); D (2.8); E (3.4); F (3.9)