7 1/2×2 2/3=15/2×8/3=20
12 1/4÷7/9=49/4÷7/9=49/4×9/7=63/4=15 3/4
20-15 3/4=19 4/4-15 3/4=4 1/4
4 1/4÷6=17/4×1/6=17/24
17/24+3 1/8=17/24+25/8=17/24+75/24=92/24=
=3 20/24=3 5/6
3 5/6+5 2/7=23/6+37/7=161/42+222/42=
=383/42=9 5/42
S6=b1 *(1-q^6)/(1-q) =4*(1-3^6)/(1-3) = 4 *(1-729)/(-2) =-2 *(-728)=1456
1)5704-3254=2450
2)4908-573=4335
3)5304-72=5232
4)=181
5)=621
6)=1253
7)=1193
8)=1182
1) на 59 минут
2) на 999мм
3) на 98см в квадрате