Math 6

Question Analysis
This question focuses on classifying numbers into sets.
The main focus is the overlap between natural and whole numbers.

Key Concept Explanation
Natural numbers: {1, 2, 3, 4, ...}
Whole numbers: {0, 1, 2, 3, 4, ...}
So natural numbers are also whole numbers.

Step-by-Step Solution
Since 4 is in both sets, the blank is filled with "whole".