Taking into account rent and other costs, a takeaway store with around $10,000 a month rent would need to sell at least about 194 portions a day to start making a profit.

This calculation is based on the following assumptions:

1. Each takeaway sells for $19, which is the average take-home unit price for boiled rice.

2. Gross profit margin is 36%, which is the average for the boiled rice takeaway industry.

3. Rent and other fixed costs are about $10,000 per month or $333 per day.

Based on these assumptions, the theoretical profit per takeaway is $7 (36% of selling price). Therefore, a minimum of about 194 takeaways would need to be sold per day (about $5,143) to cover the $10,000 per month in rent and other costs and start making a profit.

It's important to note that this calculation doesn't take into account labor costs, utilities, promotional costs, etc., which must also be taken into account and added to the cost of each takeaway, so the actual profit per takeaway could be less than $7.