I have four identical oranges. How many ways are there for me to divide these oranges into at most three groups?  (By definition, a group must have at least one orange.)
Question:
I have four identical oranges. How many ways are there for me to divide these oranges into at most three groups?  (By definition, a group must have at least one orange.)
Answer:
Let's think step by step.

user
4
I have four identical oranges. How many ways are there for me to divide these oranges into at most three groups?  (By definition, a group must have at least one orange.)
train