(10*0.9-0.9*8)+(8*0.8-0.8*6)+(6*0.7-0.7*4)+(4*0.6-0.6*2) решите рациональным

1. 0.9=9//10
2. 10*(9//10)=9
3. 0.9=9//10
4. (9//10)*8=(36//5)
5. 9-(36//5)=(9//5)
6. 0.8=8//10
7. 8//10=4//5
8. 8*(4//5)=(32//5)
9. (9//5)+(32//5)=(41//5)
10. 0.8=8//10
11. 8//10=4//5
12. (4//5)*6=(24//5)
13. (41//5)-(24//5)=(17//5)
14. 0.7=7//10
15. 6*(7//10)=(21//5)
16. (17//5)+(21//5)=(38//5)
17. 0.7=7//10
18. (7//10)*4=(14//5)
19. (38//5)-(14//5)=(24//5)
20. 0.6=6//10
21. 6//10=3//5
22. 4*(3//5)=(12//5)
23. (24//5)+(12//5)=(36//5)
24. 0.6=6//10
25. 6//10=3//5
26. (3//5)*2=(6//5)
27. (36//5)-(6//5)=6

ответ:6