How to get real value after discount. Suppose my item real value is 100. and i have given discount 10 % to my customer. Now the changed value of item id 90. If i set value 110 and give 10% discount then i got result 99. but i need result 100. What value should i set of item to get 100 after discount?

Hint:

If $x$ is the nominal price and the discount is $d$, then for $p$ the price really paied, you have: $x(1-d)=p$ so $x=\dfrac{p}{1-d}$.