Who Wants to Be the First: Hot Seat

 (Vietnamese: Ai là Đệ Nhất: Ghế Nóng) is a spin-off version of Who Wants to Be the First?, based on hot seat version of the game show Ai là Triệu Phú, named Ai là Triệu Phú: Ghế Nóng. The show began airing on Sofia the First Channel from October 1, 2020.

General knowledge number question

 * Each match consists of 3 contestants. Contestants will have 2 rounds of digital questionnaires: Placeholder round and Support round.
 * In the placeholder round, contestants will answer numerical questions within 30 seconds. The contestant who is closest to the answer or has the same answer to another contestant, but the fastest, will be given an ability to choose one of three seats. Then, the contestant who is the second closest to the answer or the same answer to the other contestant but the fastest will choose 1 of the other 2 seats. This prevents the rest of the contestants from being able to choose a seat.
 * The rest of the contestants will have to continue the second placeholder round, to determine who will be the second contestant to choose a seat.
 * In the support round, the rules are similar to the placeholder round, but only one contestant who is the closest to the answer or the same answer to the other contestant, but in the fastest time will won 1,000,000 StF to buy one of 3 lifelines: Ask the Audience, Double Dip or 50:50.
 * In some cases where the host can't determine who is the fastest, an additional question will be provided.
 * Starting on the second season, this round is now held before the taping session. This would later reported that it would be held through a Messenger group.

Season 3 changes
The third season saw a few changes to the "General knowledge number question". The support round was removed, while the placeholder round only be held once instead of twice.
 * The contestant who had the answer nearest from the correct answer (not matter it's higher or lower) will be able to choose the seat first.
 * Then, the contestant who had the answer second nearest from the correct would choose the seat, and so on.
 * The contestant who had the answer furthest from the correct answer will not be able to choose the seat.

Core rules

 * There are 12 questions with randomized difficulty. Contestants have to answer the questions correctly in order to have a chance to win the top prize. When there was a difficult question, they could use their "Pass" lifeline and the next contestant was required to answer the question and could not pass. Each contestant could only pass once. If the answer was correct, the contestant will be playing for the next prize in the money tree. If the answer was wrong, that person was eliminated, and the top prize would go down by one level.
 * Contestants who won in the Support round will be entitled to buy 1 of the 3 lifelines to help during their game: "Ask the Audience", "Double Dip" or "50:50". This only applied to the first two seasons.
 * Each contestant had 15 seconds for questions 1-2, 30 seconds for questions 3-7 and 45 seconds for questions 8-12.
 * The last contestant to answer question 12 or the last person on the hot seat would be the winner of the top prize if the answer was correct. Otherwise, the contestant would leave with 10,000,000 StF (50,000,000 StF in the third season).

Primary Lifelines

 * Pass: When there was a difficult question, contestant can use this lifeline and the next contestant is required to answer the question and cannot pass. Each contestant could only pass once.

In the first two seasons, the contestant with the 1,000,000 StF bonus from the support round can buy a lifeline when it is their turn in the Hot Seat. If a player is stuck on a question, they may return the 1,000,000 StF cheque to the host to pick one of the following lifelines:
 * Ask the Audience: When the contestant uses this lifeline, the host usually re-read the question and 4 options, and then the audience will vote with buttons A, B, C and D. After 20 seconds, a graph showing the percentage of the audience who voted for each option is displayed in the screen. After reading the host's results summary, contestants can choose to listen to the audience or not, and if using another lifeline.
 * Double Dip: The contestant can answer twice to the same question.
 * 50:50: The computer eliminates two wrong answers, leaving only one correct answer and one wrong answer.