(3,5),(5,7),(11,13),(17,19),(29,31),(41,43)
X+y=832, x=832-y
x-y=142
832-y-y=142
-2y=-690
y=345
x=932-345=487
((2 1/3 - 1 7/9) : 30/49) + 11 5/6 = 12 целых 20/27
1) 2 1/3 - 1 7/9 = 2 3/9 - 1 7/9 = 1 12/9 - 1 7/9 = 5/9
2) 5/9 : 30/49 = 5/9 · 49/30 + (1·49)/(9·6) = 49/54
3) 49/54 + 11 5/6 = 49/54 + 11 45/54 = 11 94/54 = 11 47/27 = 12 20/27