Make an estimate. Then use u. s traditional multiplication to fill in the missing numbers 21
11
875
132

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

20 percentage, you can also do it on a calculator.

Because it is the very esays way to learn