Identify the missing number within the series. 68, 72, 75, ?, 82, 86
Answer: E
Explanation: The difference between the numbers in this series alternates between 4 and 3. Therefore the fourth number in the series is 79.
Identify the missing number within the series. 11, 30, ?, 68, 87, 106
Answer: D
Explanation: The numbers in this series increase by 19 each time. Therefore the third number is 49.
Identify the missing number within the series. ?, 14, 12, 11, 11, 12
Answer: B
Explanation: The difference between the numbers in this series follow the sequence: -3, -2, -1, 0, +1, etc.
Identify the missing number at the end of the series. 0, 4, 9, 13, 18, ?
Answer: A
Explanation: The difference between the numbers in this series alternates between 4 and 5. Therefore the last number in the series is 22.
Identify the missing number at the end of the series. 5, 12, 26, 47, ?
Explanation: The difference between the numbers in this series increases by 7 each time: 7, 14, 21, etc. This will produce a difference of 28 between 47 and the next number in the series, which is therefore 75.
