1. (a) 69 (b) 66 (c) 48,94 (d) 24
2. (a) 20, 4.47 (b) 0.013, 20, 10 (c) 0.672, 0.0512
3. (a) no (b) 1/4 (c) 1/3
4. (a) 705, 293475 (b) 14100, 117390000 (c) 790500, 584514750000
5. 1/3