ok!
i'v done it 
thank you all!!!!

ok!
i'v done it 
thank you all!!!!

one last question..
How do you make the number end with two digits after the dot?
i want 10.45
and not 10.45676
?
Use the Math Block format as decimal

..... only reduce the decimals for display, store the verbatim original values to ensure the integrity of the results further down the line.
Thanks!