Exercise :: Number Series  Type 4
 Number Series  Type 1
 Number Series  Type 2
 Number Series  Type 3
 Number Series  Type 4
Find the number that fits somewhere into the middle of the series. Some of the items involve both numbers and letters
1.  Look at this series: F2, __, D8, C16, B32, ... What number should fill the blank? 

Answer: Option C Explanation: The letters decrease by 1; the numbers are multiplied by 2.

2.  Look at this series: 664, 332, 340, 170, ____, 89, ... What number should fill the blank? 

Answer: Option D Explanation: This is an alternating division and addition series: First, divide by 2, and then add 8.

3.  Look at this series: V, VIII, XI, XIV, __, XX, ... What number should fill the blank? 

Answer: Option D Explanation: This is a simple addition series; each number is 3 more than the previous number.

4.  Look at this series: 70, 71, 76, __, 81, 86, 70, 91, ... What number should fill the blank? 

Answer: Option A Explanation: In this series, 5 is added to the previous number; the number 70 is inserted as every third number.

5.  Look at this series: 8, 43, 11, 41, __, 39, 17, ... What number should fill in the blank? 

Answer: Option B Explanation: This is a simple alternating addition and subtraction series. The first series begins with 8 and adds 3; the second begins with 43 and subtracts 2.
