In the opening scene, Malcolm (accompanied by Reese) is adjusting Hal's alarm clock.
At first you clearly see a wrist/hand (Malcolm's) is not wearing a wrist watch while adjusting the alarm clock. Then it cuts to a new angle and you see Malcolm (accompanied by Reese) adjusting the alarm clock with a wrist watch and unbuttoned shirt cuff. Then as it cuts to the original angle, you see the strap of the wrist watch. As Malcolm and Reese sneak out of the room, the watch is gone again (although possibly this time covered by shirt sleeve), and the shirt cuff is buttoned.
At first you clearly see a wrist/hand (Malcolm's) is not wearing a wrist watch while adjusting the alarm clock. Then it cuts to a new angle and you see Malcolm (accompanied by Reese) adjusting the alarm clock with a wrist watch and unbuttoned shirt cuff. Then as it cuts to the original angle, you see the strap of the wrist watch. As Malcolm and Reese sneak out of the room, the watch is gone again (although possibly this time covered by shirt sleeve), and the shirt cuff is buttoned.
Malcolm, Reese & Stevie discuss going to the fair. Most times Stevie's hands are hidden in an arm fold. When (twice) viewed from Reese's left, Stevie's hands can be seen dangling on his knees.
When the kids first see the ad for the county fair Stevie says "your name written on rice" was an attraction listed. In fact it is listed as 'your name written in rice' which makes no sense and is probably a typo made when the page was mocked up.
The boys arrange to sleep over at each other's house so that each set of parents assume their kids(s) is/are at the other house, but their plan is to go to the county fair and then sneak home - but whichever house they sneak home to is a house they are not supposed to be at.