1.

1) 5/10 = 1/2 = 0,5

2) 8/32 = 1/4 = 0,25

3) 14/63 = 2/9

4) 25/40 = 5/8 = 0,625

5) 32/80 = 4/10 = 2/5 = 0,4

6) 56/72 = 7/9

7) 72/108 = 8/12 = 2/3

8) 480/640 = 48/64 = 6/8 = 3/4 = 0,75

2.

1) 8/9 17/18

16/18 < 17/18

2) 6/7 17/21

18/21 > 17/21

3) 7/12 11/15

35/60 < 44/60

4) 5/9 4/7

35/63 < 36/63

5) 7/15 13/18

42/90 < 65/90

6) 7/36 11/42

49/252 < 66/252

3.

3/8, 5/6, 7/9, 1/4

3/8 = 27/72

5/6 = 60/72

7/9 = 56/72

1/4 = 18/72

18/72, 27/72, 56/72, 60/72 или 1/4, 3/8, 7/9, 5/6

4.

x/8 < 31/48

6x/48 < 31/48

6x < 31

x < 31/6

x < 5 1/6 (5 целых одна шестая)

Ответ: (-∞; 5 1/6)