№ 778
7 14/15 + 2 1/15 = 9ц 15/15 = 10
9 24/27 + 12 13/27 = 21ц. 37/27 = 22ц 10/27
1 - 12/19 = 19/19 - 12/19 = 7/19
8 - 3 6/15 = 5 - 6/15 = 4ц. 9/15
12 - 11 6/11 = 5/11
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№779
х + 4ц. 4/9 = 6ц.2/9
х = 6ц.2/9 - 4ц.4/9 = 5ц.11/9 - 4ц.4/9
х = 1ц.7/9