The original text is mostly clear and appropriate for a 6-year-old, but a few small improvements can make it more grammatically correct and easier to read:
Original:
Inside your head is your amazing brain. Like a super computer, it controls everything in your body. Your brain knows when you’re hot or cold, when it hurts and when you’re hungry. It helps you move, knows what you like and keeps your memories.
Suggestions for improvement:
- Super computer should be one word: supercomputer.
- In the phrase "when it hurts," it’s clearer to say "when you feel pain" or "when something hurts" to specify what hurts.
- Adding a comma before the last item in a list helps clarity: "It helps you move, knows what you like, and keeps your memories." (Oxford comma)
Corrected version:
Inside your head is your amazing brain. Like a supercomputer, it controls everything in your body. Your brain knows when you’re hot or cold, when you feel pain, and when you’re hungry. It helps you move, knows what you like, and keeps your memories.