Page 226 - Maths Skills - 8

224 Maths

Exercise - 2.1

− 

1. (i)  11  2 (ii)   9   4 (iii) 3 5


 3   11 7
2. (i) 27 (ii) −243 (iii) −1 (iv) 64 (v) 256 (vi) 49 (vii) 169 (viii) −16807
125 1024 2187 343 625 4 121 3125
 9 2  8  2  7 2  5 3  −  1 3  −  3 3  16 2  2 5
3. (i)   (ii)   13  (iii)   (iv)   (v)   5   (vi)   8   (vii)   17  (viii)  

5

4
5

3

4. (i) 1 (ii) 1 (iii) 7 (iv) 3 (v) (13) 4 (vi)   7   2 (vii)   −15   3 (viii)   −  9  5
− 3 9 5 − 11  − 19  17   −  8
5. (i) −32 (ii) 16 (iii) 3176523 (iv) −1 6. (i) 3375 (ii) 28561 (iii) 3375
50421 729 1562500 96 6859 83521 64
5
7. (i) −1 (ii) 13 (iii) – 9 (iv) 42 (v) (vi) –1
9 7 3
8. (i) 1 (ii) 512 9. – 1 10. 243 11. (i) 5625 (ii) 600 (iii)   −  8  15
81 15625 64 − 5689  75 
1 64 1 448
12. (i) xy z (ii) x 13. (i) 1 (ii) (iii) (iv) (v) 1 (vi)
2
–2
400 27 10 27
Exercise - 2.2
1. (i) 0.00035 = 3.5 × 10 (ii) 3.0012 = 3.0012 × 10 (iii) 0.0001 = 1.000 × 10 –4
0
–4
(iv) 30085 = 3.0085 × 10 (v) 5.3897 = 5.3897 × 10 (vi) 0.056739 = 5.6739 × 10 –2
0
4
2
2. (i) 4.73 × 10 (ii) 6.845 × 10 (iii) 4.59731452 × 10 (iv) 3.1 × 10 (v) 8.79 × 10 (vi) 9 × 10 –12
–6
4
8
–1
3. (i) 0.0080031 (ii) 100.075 (iii) 0.00387 (iv) 70004000 (v) 0.000009813 (vi) 34567000
1
4. (i) x = –8 (ii) x = –9 5. (i) 4.348 × 10 (ii) 7.34 × 10 (iii) 1.6 × 10 –5 (iv) × 10 –10
14
5
243
4
–2
(v) 1.32 × 10 6. 1.8 ×10 times greater 7. 0.24 mm
Assessment Time
1
A. 1. (ii) 2. (ii) 3. (ii) 4. (ii) 5. (iii) B. 1. −1 2.   −  8  −18 3. 3 4.    − 5 5. 8.4 × 10 – 6
27  17   5
2
21
C. 1. T 2. T 3. F 4. T 5. T D. 1. 27 × 10 2. 1.8 × 10 3. 0.24 4. 5 × 10 sec
4
1 3
E. 1. (d) 2. (d) F. 1. − 2. 40 3. − 4. 1.673 × 10 – 30 kg 5. 3 × 10 m/s
8
8 7
3
6. 7.042 × 10 km G. 1. Jupiter > Seturn > Uranus > Neptune > Earth > Venus > Mars > Mercury 2. All planets are smaller than sun
HOTS
125 64 625 3 9
1. (i) (ii) (iii) 160,000 (iv) (v) (vi)
27 225 256 2 4
5 7 5
2. (i) (ii) (iii) 2 (iv) 6 3.
3 11 6
Chapter - 3: Squares and Square Roots
Boot-up
9
A. 1. (ii) 2. (i) 3. (ii) 4. (ii) B. 1. 2. 2.56 3. 3 × 3 × 7 × 7 4. 5
C. 1. True 2. True 3. False 4. True 8
Exercise - 3.1
1. (i) 3752 ends at 2. It is not a perfect square. (ii) 810000 ends at even number of zeros. It is a perfect square.
(iii) 64000 ends at odd number of zeros. It is not a perfect square. (iv) 4347 ends at 7. It is not a perfect square.