6 цел 3/4-2цел5/6-1цел3/8 9цел 8/15-4цел 1/12+3цел 7/20 7цел5/8+3цел2/3-8цел3/16 9цел23/25-4цел7/10-2цел1/5 20-(3цел1/6+2цел3/4) 1цел5/6+(3-1цел7/10)

1) 6 3/4 - 2 5/6 - 1 3/8 = 27/4 - 17/6 - 11/8 = 162/24 - 68/24 - 33/24 = (162 - 68 - 33)/24 =

=  61/24 = 2 13/24;

2) 9 8/15 - 49/12 +3 7/20 = 143/15 - 49/12 + 67/20 = 572/60 -245/60 + 201/60 =

= (572 - 245 + 201)60 = 528/60 = 8 48/60 = 8 4/5 = 8,8; 

3) 7 5/8 + 3 2/3 - 8 3/16 = 61/8 + 11/3 - 131/16 = 366/48 + 176/48 - 393/48 = 

= (366 + 176 - 393)/48 = 149/48 = 3 5/48; 

 4) 9 23/25 - 4 7/10 - 2 1/5 = 248/25 - 47/10 - 11/5 = 496/50 - 235/50 - 110/50 = 

= (496 - 235 - 110)/50 = 151/50 = 3 1/50; 

 5) 20 - (3 1/6 + 2 3/4) = 20 - 3 1/6 - 2 3/4 = 20 - 16/6 - 11/4 =240/12 - 32/12 - 33/12 =

= (240 - 32 - 33)/12 = 175/12 = 14 7/12;

6) 1 5/6 + 3 - 1 7/10 = 11/6 + 3 - 17/10 = 55/30 + 90/30 - 51/30 = (55 + 90 - 51)/30 = 

= 94/30 = 3 4/30;

7) 2 1/8 + 8 1/12 - 5 5/6 = 17/8 + 97/12 - 35/6 = 51/24 +194/24 - 140/24 = 

= (51 + 194 - 140)/24 = 105/24= 4 9/24 = 4 3/8;

8) 3 3/5 + 3 11/15 - 1/12 = 18/5 + 56/15 - 1/12 = 216/60 + 224/60 - 5/60 =

= (216 + 224 - 5)/60 = 435/60 = 87/12 = 7 3/12 = 7 1/4 = 7,25;