29 + 10/7 = 203/7 + 10/7 = 213/7 = 30 целых 3/7
1/3-1/5 = ( 1 * 5 ) / (3 * 5) - ( 1 * 3 ) / (5 * 3) = 5/15 - 3/15 = 2/15
<span>1/3-1/6 = ( 1 * 2 ) / (3 * 2) - 1 / 6 = 2/6 - 1/6 = 1/6 </span>
<span>1/4-1/7 = ( 1 * 7 ) / ( 4 * 7) - (1 * 4 ) / ( 7 * 4 ) = 7/28 - 4/28 = 3/28
</span>понятно 6 или 7 класс!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
-750, 150, -30, 6, -1.2
-750+150-30+6-1.2=625.2
120 :(27+3)=4(ч) - время в пути теплохода
541,
90 : (20-2)=5(ч) - потребуется лодке