№1
2 1/5+3 2/3=11/5+11/3=(33+55)/15=88/15=5 13/15
4 2/3+5 4/7=14/3+39/7=(98+117)/21=215/21=10 5/21
№2
2-1/3=2/1-1/3=(6-1)/3=5/3
3 6/7-2 8/9=27/7-26/9=(243-182)/63=61/63
№3
3 7/9-2/3=34/9-2/3=(34-6)/=28/9
34/9+28/9=62/9= 6 8/9
№4
х+3 2/5=14 1/6
х=14 1/6-3 2/5=85/6-17/5=(425-102)/30=323/30=10 23/30
х=10 23/30
№5
(11 2/3-8 3/4)+(3 1/3+2 5/6)-4 7/12=2 2/3
11 2/3-8 3/4=35/3-35/4=(140-105)/12=35/12
3 1/3+2 5/6=10/3+17/6=(10+17)/6=27/6
35/12+26/6=(35+52)/12=87/12
87/12-55/12=32/12=8/3=2 2/3