How to calculate the child precent vs it's parent ?

[yanivvl0]

Hi everyone ,

is there a way to calculate the child precent vs it's parent ? ,

for example

parent	a=50			parent	b=200
children	a1=20, a1%=40	a2=30, a2%=60		children	b1=20, b1%=10	b2=180, b2%=90

i'm sure u have perfect solution 4 me ,

thanks a lot.