Это обыкновеные дроби-(7/16+3/8)-(7/8-27/32) и второе (8/21+11/14)-(4/7-5/14)

1. 1) 7/16 + 3/8 = 7/16 + 6/16 = 13/16     2) 7/8 - 27/32 = 28/32 - 27/32 = 1/32     3) 13/16 - 1/32 = 26/32 - 1/32 = 25/32 2. 1) 8/21 + 11/14 = 16/42 + 33/42 = 49/42     2) 4/7 - 5/14 = 8/14 - 5/14 = 3/14     3) 49/42 - 3/14 = 49/42 - 9/42 = 40/42 = 20/21

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