Page 225 - Maths Skills - 7

Answers

Chapter - 1: Integers

Boot-up
A. 1. (iv) 2. (ii) 3. (ii) 4. (iii) B. 1. negative 2. greater 3. less 4. (–8)
C. 1. F 2. T 3. F 4. T

Exercise - 1.1
1. (i) + 2000 (ii) – 800 (iii) + 200 (iv) – 700 2. (i) –10°C, – 2°C, + 30°C, + 20°C, – 5°C
(ii) Kargil (iii) Delhi, Surat
3. (i) – 6, – 5, – 4, – 3, – 2, – 1 (ii) – 3, – 2, – 1, 0, 1, 2, 3 (iii) – 14, – 13, – 12, – 11, – 10, – 9
(iv) – 29, – 28, – 27, – 26, – 25, – 24

Exercise - 1.2
1. (i) 194 (ii) –597 (iii) –142 (iv) 250 2. (i) –754 (ii) –760 (iii) 2036 (iv) –2095
3. (i) –22 (ii) –256 (iii) 0 (iv) 69 4. (i) 4 (ii) 0 (iii) 9 (iv) 8 5. 20 6. 6400 m
7. –17 and 2 (answer can vary) 8. –7 and 4 (answer can vary) 9. Both team scored equal
10. (i) –7 (ii) 82 (iii) –19 (iv) – 4
Exercise - 1.3
1. (i) – 63 (ii) 0 (iii) 0 (iv) – 496 (v) 414
2. (i) – 260 (ii) 429 (iii) – 180 (iv) 254300
3. (i) 10 (ii) – 5 (iii) 6 (iv) 3
4. (i) Positive (ii) No sign (iii) Negative (iv) Positive
5. (i) 66 (ii) 0 (iii) 300 (iv) – 32 6. 8°C 7. (i) 50 marks (ii) 17 marks
Exercise - 1.4
1. (i) 2 (ii) – 3 (iii) – 49 (iv) 204 (v) 3 (vi) 0
2. (i) – 309 (ii) 84 (iii) – 5 (iv) 0 (v) – 56 (vi) – 327
3. (i) True (ii) True (iii) False (iv) False (v) False (vi) False
4. (i) 1 (ii) 1 (iii) – 19 (iv) 9 5. At 4 a.m. temp = 4°C and at 12 noon temp = 20°C.
6. (i) 32 marks (ii) 6 questions
Exercise - 1.5
1. (i) – 2 (ii) – 17 (iii) 31 (iv) 28 (v) 5 (vi) 117
2. (i) 67 (ii) 11 (iii) 5 (iv) 731 (v) 86 (vi) – 29
Assessment Time

A. 1. (i) 2. (iv) 3. (ii) 4. (ii) 5. (i) B. 1. negative 2. 50 3. Positive 4. 1 5. 15
C. 1. F 2. T 3. F 4. T 5. T D. 1. 213 km 500 m 2. 36800 ton
3. 144 million E. 1. (c) 2. (b) F. 1. gain ` 1,47,200 2. 15 minutes 3. decrease of 2,000 feet; 18,000 feet
4. 31 marbles G. Planet Mean Temperature (°F) Mean Temperature (°C)
Mercury 333 167.22
Venus 867 463.88
Earth 59 15
Mars –85 –65
Jupiter –166 –110
Saturn –220 –140
Uranus –320 –195.55
HOTS Neptune –330 –201.11
1. decrease of 10 points 2. ` 1,550 3. (i) 5°F (ii) 59°F (iii) – 40°F
4.
× 1 –2 3 –4 ÷ 0 6 –12 18
0 0 0 0 0 1 0 6 –12 18
1 1 –2 3 –4 –2 0 –3 6 –9
3 3 –6 9 –12 –6 0 –1 2 –3