A mutual fund unit's price: the fund's assets minus its liabilities, divided by the units in issue.
A fund declares its NAV at the end of each business day. Units are bought and sold at the NAV that applies to the day of the transaction under SEBI's cut-off rules, and the fund's expenses have already been taken out of it.
A low NAV does not make a fund cheap. Two funds holding the same shares grow by the same percentage whatever their NAVs; what you own is a share of the portfolio, not a number of units.
Figures on this page are filled from the same tax and scheme tables the calculators use, for the current financial year. Every term in the glossary.