a) 162:9 - 7 < 162:(9-7)
18-7 < 162:2
11 < 81
b) (40-30):10 < 40-(30:10)
10:10 < 40-3
1 < 37
c) 68-12×(4-6:2) [68-(12×4-6)]
68-12×(4-3) > [68-(48-6)]
68-12×1 > 68-42
68-12 > 24
56 > 24
d) (100-10):10+90:3 > [(100-10):10+90]:3
90:10+30 > [90:10+90]:3
9+30 > [9+90]:3
39 > 99:3
39 > 33