:6,3 * 1целая 2/9. 11,7 * 1целая 6/7.

6,3 = 6целых 3/10 = 63/10
1целая 2/9 = 11/9
63/10  * 11/9 = (63 *11) / (10 * 9 ) = 77/10 = 7 целых 7/10 = 7,7

11,7 = 117/10
1целая 6/7 = 13/7
117/10 * 13/7 = (117 * 13) / (10 * 7) = 1521/70 = 21целая 51/70

6,3 * 1 целую 2/9 = 63/10 * 11/9 = 77/10 = 7,7.
(6,3 = 63/10;
1 целая 2/9 = 11/9).

11,7 * 1 целую 6/7 = 117/10 * 13/7 = 1521/70.
(11,7 = 117/10;
1 целая 6/7 = 13/7).