[amp_mcq option1=”21″ option2=”13″ option3=”9″ option4=”11″ correct=”option1″]
The missing number is 11.
The numbers in the sequence are all the prime numbers less than 20, except for 13. 11 is the next prime number after 13.
A prime number is a natural number greater than 1 that is not a product of two smaller natural numbers. A natural number greater than 1 that is not prime is called a composite number.