Every year on the holiday of Simchat Torah, three different portions of the Torah are read during the morning service. a) V'zot Haberacha, the last portion of the Torah; b) the holiday maftir reading, discussing the day's Temple service; c) Bereishit, the first portion of the Torah. If a synagogue has three Torah scrolls, then each of these portions is read from another scroll. If not, then one of the scrolls is quickly rolled from one portion to the next between readings.

There are three other times during the course of a year when, if various calendric variables fall in place, three portions of the Torah are read on the same day:

1. When Rosh Chodesh Tevet is on Shabbat. Since the month of Tevet always begins during the holiday of Chanukah, in such a case there would be three readings: a) The weekly reading. b) The reading for Rosh Chodesh (head of the month). c) The holiday reading.

2. When the month of Adar (or the second month of Adar in a leap year) begins on Shabbat. The extra portion of Shekalim is always read on the Shabbat immediately preceding the month of Adar, or on Rosh Chodesh Adar itself when it falls on Shabbat. On such a week we would read: a) The weekly Torah portion. b) The reading for Rosh Chodesh. c) The Shekalim reading.

3. Same thing when the month of Nissan begins on Shabbat. The extra portion of Hachodesh is read on the Shabbat immediately preceding the month of Nissan, or on Rosh Chodesh Nissan when it falls on Shabbat. On such a Shabbat, the weekly Torah portion is read, in addition to the Rosh Chodesh and Hachodesh readings.

In any of these cases, three Torah scrolls are taken out of the Ark, if the synagogue has that many.

All the best,

Rochel Chein for Chabad.org