А) 3/16+5/24; б) - 3/16-5/24; в) - 3/16+5/24; г) 3/16-5/24

5/21+4/9; - 5/21-4/9; 5/21-4/9; - 5/21+4/9

7/12+1/18 - 7/12-1/18 - 7/12+1/18 7/12-1/18

1) 3/16+5/24=9/48+10/48=19/48

2) - 3/16-5/24 = - 9/48-10/48=-19/48

3)

-3/16+5/24=-8/48+10/48=2/48 = = 1/21

4) 3/16-5/24=9/48-10/48=-1/48

5) 5/21+4/9=15/63+28/63=43/63

6) - 5/21-4/9=-15/63-28/63=-43/63

7) 5/21-4/9=15/63-28/63=-13/63

8) - 5/21+4/9=-15/63+28/63=13/63

9) 7/12+1/18 = 21/36+2/36=23/36

10) - 7/12-1/18=-21/36-2/36=-23/36

11) - 7/12+1/18=-21/36+2/36=-19/36

12) 7/12-1/18=21/36-2/36=19/36