Hi,

In improvement examination or even if you are repeating the class, the practical examination marks are taken from previous examination held. Like, if you have done your class 12 already and have practicals too, same marks will be carry forwarded in the improvement examination. No separate practicals are conducted for improvement examination. So, your percentage will be calculated out of 500 marks only. If practical for English and Maths were not held previously, then you can convert your 80 marks into 100 marks and your obtained marks similarly can be converted out of 100.