Increase 37 by 15% please

In order to increase a number by  15% ,
multiply it by  1.15 .

37  x  1.15  =  42.55 .

Where does the  1.15  come from ?

The ' 1 ' is the entire number that you started with,
and the  " .15 " is the additional  15%  of it.

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