How could you find out which weighs more one ton of pillows or one ton of bowling balls?

You can put them on a scale and compare them.   Or you can figure out the weight of one individually.  A ton of pillows won't suddenly increase in weight compared to the bowling balls.

1. 0.3 •4 is the same as 4 groups of 0.32. 7•0.8 is the same as 7 groups of 0.83. it increases by 0.5 every time, so 0.5x4 it increases by 0.9 every time, so 0.9x5. 0.9•12=10.86. 0.47•5=2.35i can finish the next ones in a separate post