9*3=27-20=7*9=63-23=40:10=4*6=24:3=8*10=80-30=50
<span>1400*7-57960:46=8540
</span><span>39078:13+49*46=14053
</span>
А.)27 - 12 = 15
42 - 15 = 27
27 + 27 = 54
54 - 12 = 42
б.) 115 - 35 = 80
80 - 39 = 41
35 + 41 = 76
115 - 76 = 39
в.) где то ошибка
г.) 28 + 35 = 63
63 - 53 = 10
28 - 10 = 18
18 + 35 = 53