Well, that is the number of seats to be reserved for women in Lok Sabha in the first round if the women’s reservation bill is passed.  The rules for determining number of seats to be reserved are as follows.

1. The Bill does not reserve one-third of seats on an All-India basis.  It reserves “as nearly as possible, one-third” of seats in each state.
2. Also, it reserves “as nearly as possible, one-third” of seats reserved for Scheduled Castes in any state for women, and similarly for ST women.  If any state/UT has only 1 seat in any of these categories, that seat will be reserved in the first election, and be open to men in the subsequent two elections.  If a state has 2 seats in any category, one of these will be reserved for women in the first election, the other in the second, and neither in the third election.  One of the two seats nominated for Anglo-Indians will be reserved after the first and second elections.
3. The reservation for general category seats will be done after following Rules 1 and 2 above.  However, if a state has one or two general category seats, they follow rules similar to that for SC and ST seats (cycling through three elections).

Example 1:  Puducherry has one general seat.  This will be reserved for women in the first election and open in second and third elections. Example 2:  Manipur has two seats, of which one is reserved for STs.  Thus, both seats will be reserved in the first election and open in the second and third elections. Example 3:  Delhi has seven seats:  six general and one SC.  In the each election 2 seats (seven divided by three, rounded to nearest integer) will be reserved.  In the first election, one general and one SC seat will be reserved, and in the next two elections, two general seats will be reserved. We compute that this results in 192, 179 and 175 seats (out of 545) being reserved for women in the first three elections. A similar computation shows that 1367, 1365 and 1364 (out of 4090 seats of the legislative assemblies of 28 states and Delhi) will be reserved for women in the first three elections. Excel file with detailed computation is available here.