R + 12 705 : 121 = 105
r + 105 = 105
r = 105 - 105
r = 0
-----------------------
Проверка: 0 + 12 705 : 121 = 105
0 + 105 = 105
7*7*7=343объем 6*7*7=294 пл поверхности
8 <span>4/9</span>−3 <span>7/9</span>=<span>8 · 9 + 4/9</span>−<span>3 · 9 + 7/9</span>=<span>76/9</span>−<span>34/9</span>=<span>76 − 34/9</span>=<span>42/9</span>=<span>14 · 3/3 · 3</span>=<span>14/3</span>=4 <span>2/<span>3</span></span>
119- 31=88 книг 88: 2 = 44 книг на первой полке
44+31=75 книг на второй полке