Billy is 4 years old. he has a big box of legos, and his mother asks him to give her 5 legos from the box. he has trouble deciding how many to give her so he takes a handful and says, "here, it's five." what is billy's problem with this task?

I believe the answer is: 4-year-olds do not have a scheme for conservation of numbers.
Scheme refers to a mental structure that influence the way people arrange a certain information in our mind.
On average, this ability started to develop at the age of 6, so it's very unlikely a 4 year-old would has the ability to create scheme for number conservation

Lol passover. jewish holiday. hope this !