7-8 .
: : - - - 8-9 - 811 - 7-8 - - . 1 6 2 6 = 12 3 (1, ) 6 = 18 5 (2, ) 6 = 24 6 (3, ) 6 = 30 7 (4, ) 6 = 36 8-15 = 36 4 , 16, 19 22 =24 . 23-25 = 24 7 8 , . . = 12 . 30 , , . . . , . - , . , . . , 4 6-7 . . . 9 . . . . .