Identify the missing number.
7 8 20 ? 5 6 2 3
Answer: B
Explanation: The numbers in the boxes on the left add up to 26. The answer must be 1 to make the numbers in the boxes on the right add up to 26.
22 22 44 1 13 3 6 ?
Answer: D
Explanation: The numbers in the boxes on the left add up to 60. The answer must be 9 to make the numbers in the boxes on the right add up to 60.
4 8 8 16 16 12 ? 24
Explanation: Starting from the number on the top left, move clockwise adding the number in the first position each time. The answer is 32 which is 24 + 8.
Identify the missing number within the series. 54, 40, 28, ?, 10, 4
Answer: C
Explanation: The difference between the numbers in this series decreases by 2 each time: -14, - 12, -10, -8, etc. The fourth number in the series is therefore 18.
Identify the missing number within the series. ?, 30, 35, 25, 30, 20
Answer: A
Explantion: The difference between the numbers in this series alternates between -5 and -10. Therefore the first number in the series is 40.
