Hint: First list the whole numbers and later differentiate the whole numbers as prime numbers and composite numbers to find the smallest composite number.
Complete step by step answer:
All composite numbers have at least three factors; this means that there are at least three numbers that can be used to evenly divide a composite number.
Factors of 21 are 1,3,7,21.
Hence smallest composite no is 4.
1 has only one factor
2 has 2 factors i.e 1 and 2.
Also, 3 has 2 factors i.e 1 and 3.
So, 4 is the first number that satisfies all the conditions to be a composite number.
Factors of 4 are 1,2,4.
NOTE: A composite number is a positive integer that can be formed by multiplying two smaller positive integers equivalently, it is a positive integer that has at least one divisor other than 1 and itself.