What will come in place of question mark in the following series 2 3 6 15 42?

Missing numbers are the numbers that got missed in the given series of numbers with similar differences among them. The process of writing the missing numbers is termed as finding similar changes between those numbers and filling their missing values in their specific series and places. In this article, we are going to find the missing numbers in the sequence and series with examples.

• Number Lines
• Cardinal Numbers
• Fibonacci Numbers
• Cube Root of Numbers

Missing Number Problems

Go through the problems given below to find the missing numbers.

Example 1:

Write the missing number in the given sequence.

2, 3, 6, 4, 5, 20, ? , 3, 18.

Solution:

The missing number is found to be as 6.

This is because a relationship between the numbers in the given series is determined as the third digit ‘6’ which is the product of the first two digits ‘2’ and ‘3’, the sixth digit ‘20’ is the product of fourth digit ‘4’ and fifth digit ‘5’ and the ninth digit ‘18’ is the product of the seventh digit ‘6’ and eighth digit ‘3’

Therefore, the seventh digit should be “6”.

The series is 2, 3, 6, 4, 5, 20, 6, 3, 18.

Example 2: Find the missing number in the following number line: 1, 3, 9, 15, 25,? , 49.

Solution:

The missing number is found to be 35

This is because all the sequence of numbers are squares and (squares – 1) alternatively like

1 square = 1,

2 square = 4 and then 4 – 1 = 3,

3 square = 9,

4 square = 16 and then 16 – 1 = 15,

5 square = 25,

6 square = 36 and then 36 – 1 = 35

7 square = 49.

Therefore, the number line will be 1, 3, 9, 15, 25, 35, 49.

Example 3: Find the missing number in the following sequence 5, 7, 11, ?, 17, 19

Solution:

The missing number is found to be 13.

This is because all the given orders of numbers in a number line contain the prime numbers 5, 7, 11, 13, 17, 19 which are all divisible by only ‘1’ and itself.

Therefore, the number line series will be 5, 7, 11, 13, 17, 19.

Video Lesson on Numbers

Find the Missing Numbers

1. Complete the following number series by writing their missing numbers 6, 3, 2, 4, 4, 1, ?, 3, 3.

2. Complete the following number series by writing their missing numbers 5, 3, 2, ?, 1, 3, 3, 3, 0.

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