A+b
40+35=75
60+48=108
500+499=999
a-b
40-35=5
60-48=12
500-499=1
B=70
70+20=90
14+70=84
80-70=10
70-9=61
b=23
23+20=43
14+23=37
80-23=57
23-9=14
b=11
11+20=31
14+11=25
80-11=69
11-9=2
(2,1:98)*х=18
3/70х=18
х=18*70/3
х=420
23x+456=732
23x=732-456
23x=276
x=276/23
x=12