(a) General rule
Where it is not otherwise provided by this title, the Secretary shall, as soon as practicable, and within 60 days, after the making of an assessment of a tax pursuant to section 6203, give notice to each person liable for the unpaid tax, stating the amount and demanding payment thereof. Such notice shall be left at the dwelling or usual place of business of such person, or shall be sent by mail to such person's last known address.

(b) Assessment prior to last date for payment
Except where the Secretary believes collection would be jeopardized by delay, if any tax is assessed prior to the last date prescribed for payment of such tax, payment of such tax shall not be demanded under subsection (a) until after such date.