Даю 21 балл!!! Пример а.
1) 2,3+5,8=8,1 2) 8 1/10 * 3 5/7= 81/10 * 26/7= 2106/70 3) 4,9-2,3=2,6 4) 2 6/10 / 7/9 = 26/10 * 9/7= 234/70 5) 2106/70 / 234/70 = 2106/70 * 70/234 = 2106/70 / 234 = 9