А) 1/4 * 4 3/4 * 16/57 + ( 4 3/4 + 1 2/3 ) * 16/21 + 2/27 + 4 1/2
1) (19/4+5/3)=(57+20)/12=77/12;
2) 77/12*16/21=11/3*4/3=44/9;
3),4) 1/4*19/4*16/57=1/4*1/4*16/3=1/3;
5) 1/3+44/9=47/9;
6) 47/9+2/27=141/27+2/27=143/27;
7) 143/27+9/2=286/54+243/54=529/54=9 43/54.
<span>б) ( 4/5 + 1/6 ) * ( 23 2/3 - 15 5/9 ) * 45/58 - 1/2 =</span>
1) 4/5+1/6=24/30+5/30=29/30;
2) 23 2/3 - 15 5/9=8 (6-5)/9=8 1/9;
3),4) 29/30*73/9*45/58=73/6;
5) 73/6 - 1/2=73/6 - 3/6=70/6=11 4/6= 11 2/3.
Оно увеличится на 12 целых 7/33
по моему так
4 * 120 = 4 * (100 + 20) = 4 * 100 + 4 * 20 = 400 + 80 = 480
3 * 230 = 3 * (200 + 30) = 3 * 200 + 3 * 30 = 600 + 90 = 690
в 1 и 2,в 1 и 3,в 1 и 4 ,во 2 и 3,во 2 и 4,в 3 и 4.