There is currently no Super Mario Galaxy 3. If you mean Super Mario Galaxy 2 there are 242 stars.
There's 150 power stars in Super Mario 64 DS.
Although there are 150 stars in total, you only need 80 stars (and Mario) to complete the game as this is the number of stars you need to get into the final Bowser level.
There are 4, Super Mario Bros. 1, Super Mario Bros. 2 and Super Mario Bros. 3, there is also Super Mario Bros. The Lost Levels which is the original Super Mario Bros. 2 in Japan. They have also made a remake of Super Mario All-Stars for Nintendo Wii.
Rosalina is not in Super Mario Kart. She is in Mario Kart Wii.
6 stars
There is no specific number needed to make the city to flood. You have to go into every level and defeat Shadow Mario.
122 power stars and 120 green stars.
any number of stars with luigi or all 150 stars
In Super Mario Galaxy 1 you can get 121 power stars, but in Super Mario Galaxy 2 the star gauge can hold 240 stars.
120.
5