Continuity mistake: As Steve Martin is ripping out pages in the phone book about babysitting services, if you look closely, you can see that it is the same page over and over again just shot at different angles.
Continuity mistake: When Hank is being attacked by the dog and the family is looking on and laughing, it cuts to Charlie laughing and he is holding a glass to take a drink, then it cuts back to Hank, and just a second later it cuts back to the family at the table and Charlie is sitting with his arm across his chair facing a completely different way, with nothing in his hands. There is no way he could have put down his glass and turned to lean back with his arm across the chair in that short of time. (00:40:20)
Continuity mistake: When the dad first gets into the bouncy castle to get his daughter, you notice him fall forward but then half a second later, he is standing up as if nothing happened.
Continuity mistake: When Beans, the frog, is just sitting on the pebbles and Mark is going, "Are you all right?", the the pebbles are bunched up on one end of the aquarium. But, in the shot where Mark goes back to his room AFTER Beans dies, the pebbles are bunched up on the other side.
Continuity mistake: At the kitchen table, Kate is throwing toast, and she throws one piece at Kim (the twin) who catchs it. Yet in the very next wideshot Kim is leaning on the table, with no toast in her hands, and Kate throws Kim another piece of toast again. (00:08:10)
Continuity mistake: When the teenage boy picks up the picture of him and his girlfriend, the position of the picture in his hand changes between shots.
Continuity mistake: After the scene where the kids get grounded, there is a scene of Mark laying in bed. He then rolls over in bed and stares at a picture of him and his mum. In front of the picture are his glasses, but in the very first overhead shot of Mark laying in bed, the glasses weren't in front of the picture. (01:01:00)
Continuity mistake: When Tom is being interviewed on TV, it cuts to Lorraine who says "At least we get to see him on TV" and she has both her legs bent up in front of her. In the following wideshot of the 8 kids and Kate on the bed, Lorraine only has one leg bent up in front of her. (00:27:55)
Continuity mistake: When the chandelier breaks and Tom falls whilst holding it, between shots the chandeliers lights go from being pretty much intact, to being totally smashed - and this is after the fall, so there is no reason for them to smash any more. The long yellow rope that attachs the chandelier to the ceiling changes the position it lays between the closeup of Tom landing (obviously not Steve Martin) and the following wideshot too. (00:24:25)
Continuity mistake: When Bonnie Hunt announces that Mark has run away, she has no paper in her hand. It cuts to Steve Martin, then back to Bonnie who now has Mark's note against her chest. (01:17:05)
Continuity mistake: When Tom and the family are getting ready for Oprah to come round, Tom is on the phone to Kate and he runs over to a vase of yellow flowers and nearly knocks them to the ground. Between shots the way he touchs the flowers changes. (01:08:50)
Continuity mistake: When Tom picks the kids up from school, Mark hands his dad a picture. In a closeup Mark is holding the piece of paper at the top, yet in the wideshot he is holding it at the side. (00:54:30)
Continuity mistake: When Tom is in an office at the Stallions, Charlie comes in and he says "Dad we need to talk" and then he picks up a rugby ball with one hand. In the following closeup though he suddenly is holding it with both hands. (00:53:35)
Continuity mistake: When Nora and Hank are standing by the bainster, when the whole family is fighting, in one shot Nora's arms are down by her side, but in the next shot, her hand is up by her chest. (01:15:35)
Continuity mistake: When the Baker kids are taking revenge on the bullies that stole Mark's glasses, they knock the guy's drink to the ground, but a couple shots later it's gone.
Continuity mistake: As Hank falls into the paddling pool he clearly drops the apple he was holding into the pool, yet in the following closeup he has the apple in his right hand. (00:34:15)
Continuity mistake: When Nora is on the phone to the Bakers, trying to find a way not to visit them, she talks to Hank whilst covering the phone mouthpiece, and on the side are three blue candleholders, yet in some shots one of the candleholders disappears. (00:30:30)
Continuity mistake: When Steve Martin is talking to Bonnie Hunt about being gone for three days, watch the picture on the table. It moves closer to the edge of the table in the subsequent shot. In the first shot it is not covering the ring on the edge of the table, in the next shot it is. (00:43:10)
Continuity mistake: When Beans the frog has been caught, Tom gives Mark the net with the frog in and then Mark smashes all of the glass/ornaments on the shelf, by swinging the handle of the net into them. Look at the mess of glass/ornaments on the side, just after Mark smashes them. When we see the shelf again, the position of the smashed glass/ornaments on the side had changed greatly, and things have appeared/disappeared. (00:09:45)
Continuity mistake: When Hank is tripped by the hose, his hair goes from dry to suddenly wet just before he hits the water. (00:35:40)
Answer: Because he needed a way to coach the team while also watching his kids.