1) 3/14 - 8/21 + 5/7
= 27/98 - 32/98 + 35/98
= $27-32+35$/98
= 30/98
= 15/49

2) 14/55 33/50 : 1 24/25
= $14/55</em>33/50$ / $1+24/25$ = $462/2750$ / $49/25$ = $462/2750$ * $25/49$ = 11550/134750
= 231/2695

3) -2 5/12 + 11/18 - 1/6
= -29/12 + 11/18 - 1/6
= -174/72 + 44/72 - 12/72
= -142/72
= -71/36

4) 11/40 : 1 7/26 35/39
= 11/40 / 33/26 35/39
= 11/40 26/33 35/39
= 1001/34320

5) 2/15 - 1 1/5 + 4/3
= 2/15 - 6/5 + 4/3
= 2/15 - 18/15 + 20/15
= 4/15