Odpowiedź:
4. 6 * 3 5/18 = 6 * 59/18 = 1 * 59/3 = 59/3 = 19 2/3
5. 2 7/12 * 8 = 31/12 * 8 = 31/3 * 2 = 62/3 = 20 2/3
6. 5/7 * 4/9 = 20/63
7. 2/5 * 7/8 = 1/5 * 7/4 = 7/20
8. 3/10 * 7/9 = 1/10 * 7/3 = 7/30
9. 6/15 * 5/8 = 2/3 * 1/4 = 2/12 = 1/6
10. 5/12 * 4/25 = 1/3 * 1/5 = 1/15
11. 3/10 * 5/6 * 4/7 = 1/2 * 1/2 * 4/7 = 1/2 * 1 * 2/7 = 2/14 = 1/7
