Income from profession - p&l balancesheet

Dear All,

If any person is earning income from any profession like tuition, estate agent, consultancy but does not maintained any books as such, is it still necessary for him to prepare profit & loss account and balancesheet? or

can he estimate his expenses at a certain percentage of gross receipts and rest of the income as a taxable income? and file the ITR 4 under "no books of accounts maintained".

Please guide and elaborate.

Regards,

Suraj