A = {1; 3; 5; 7; 9}
B = {1; 2; 3; 4; 5; 6; 7; 8; 9; 10; 11; 12; 13; 14; 15; 16; 17; 18; 19; 20}
C = {10; 20; 30; 40; 50; 60; 70; 80; 90}
630÷6+78×2=261
500-106-99=295
55*2÷10=11
84÷12*2=14
(489-309)÷2=90
2х=148:2
2х=74
х=74:2=37
3+х=80*3
х=240-3
х=217
х-17=59-1
х=58+17
х=75
1000:х=50-10
х=1000:40
х=25