on 40)
15*38 is indeed 570, however you have two decimals from 0.15, so you move two decimals over, 5.70.
on 42)
160*75 is indeed 12000, however you have two decimals as well, from 0.75, thus 120.00
43)
you have two decimals again, from 0.24, so is 8.4.
44)
again, you have two decimals, though 2*74 is indeed 148, if we move the dot two decimals over, is 1.48.