Practice Questions: Series Completion and Inserting | Math Olympiad for Class 5 PDF Download

Q1: Direction: In the following question, a series is given. One figure of this series is missing. Fill in the blanks to complete this series.

(a)
(b)
(c)
(d)
Ans: (b)
Explanation: All the small squares are removed from the right most column and lower most row alternately.

Q2: Direction: In the following question, a series is given. One figure of this series is missing. Fill in the blanks to complete this series.

(a)
(b)
(c)
(d)
Ans: (a)
Explanation: A square is added inside with alternate shades.

Q3: Direction: In the following question, a series is given. One figure of this series is missing. Fill in the blanks to complete this series.

(a)
(b)
(c)
(d)
Ans: (c)
Explanation: In each next step one dot and one bar is added. The dots are stuck to the last bar is commencing with bottom and top alternately.

Q4: Direction: In the following question, a series is given. One figure of this series is missing. Fill in the blanks to complete this series.

(a)
(b)
(c)
(d)
Ans: (b)
Explanation: The number of sides in the figure increases by one in each step.

Q5: Direction: Find the number which will replace the '?' mark.

(a) 22
(b) 30
(c) 32
(d) 31
Ans: (c)
Explanation: Clearly, we have

So, missing number=

Q6: Direction: In the following question, a series is given. A term in series is missing. Find the missing term from amongst the options.
18, 17, 19,?, 20, 15, 21, 14
(a) 16
(b) 17
(c) 18
(d) 19
Ans: (a) 16
Explanation: Observing the sequence, it appears that the numbers are alternating between increasing and decreasing. Specifically, the pattern seems to be:
Subtract 1
Add 2
Subtract 3
Add 4
Following this pattern:
18 - 1 = 17
17 + 2 = 19
19 - 3 = 16
(16) + 4 = 20
20 - 1 = 19
19 + 2 = 21
21 - 3 = 18
(18) + 4 = 22
So, the missing term in the sequence should be 16. Therefore, the correct answer is A) 16.

Q7: Direction: In the following question, a series is given. A term in series is missing. Find the missing term from amongst the options.
1, 5, 13, 25, 41, ?
(a) 52
(b) 58
(c) 61
(d) 62
Ans: (b) 58
Explanation: Observing the sequence, it appears that the numbers are increasing in a specific pattern. Let's analyze the differences between consecutive terms:

• The difference between 5 and 1 is 4.
• The difference between 13 and 5 is 8.
• The difference between 25 and 13 is 12.
• The difference between 41 and 25 is 16.

It seems like the differences are increasing by 4 each time. Therefore, following this pattern:
The difference between the next term and 41 should be 16 + 4 = 20.
So, to find the missing term:
41 (last term) + 20 = 61.
Therefore, the correct answer is C) 61.

Q8: Direction: In the following question, a series is given. A term in series is missing. Find the missing term from amongst the options.
10, 18, 28, 40, 54, 70,?
(a) 85
(b) 86
(c) 87
(d) 88
Ans: (d)  88
Explanation: To find the pattern in the given sequence, let's analyze the differences between consecutive terms:

• The difference between 18 and 10 is 8.
• The difference between 28 and 18 is 10.
• The difference between 40 and 28 is 12.
• The difference between 54 and 40 is 14.
• The difference between 70 and 54 is 16.

It appears that the differences are increasing by 2 each time. Following this pattern:
The difference between the next term and 70 should be 16 + 2 = 18.
So, to find the missing term:
70 (last term) + 18 = 88.
Therefore, the correct answer is D) 88.

Q9: Direction: In the following question, a series is given. A term in series is missing. Find the missing term from amongst the options.
6, 11, 21, 36, 56,?
(a) 42
(b) 51
(c) 81
(d) 91
Ans: (c) 81
Explanation: To identify the pattern in the given sequence, let's examine the differences between consecutive terms:

• The difference between 11 and 6 is 5.
• The difference between 21 and 11 is 10.
• The difference between 36 and 21 is 15.
• The difference between 56 and 36 is 20.

It appears that the differences are increasing by 5 each time. Following this pattern:
The difference between the next term and 56 should be 20 + 5 = 25.
So, to find the missing term:
56 (last term) + 25 = 81.
Therefore, the correct answer is C) 81.

Q10: Direction: In the following question, a series is given. A term in series is missing. Find the missing term from amongst the options.
2, 5, 9, ?, 20, 27
(a) 14
(b) 16
(c) 18
(d) 24
Ans: (a) 14
Explanation: To identify the pattern in the given sequence, let's examine the differences between consecutive terms:

• The difference between 5 and 2 is 3.
• The difference between 9 and 5 is 4.

It appears that the differences are increasing by 1 each time. Following this pattern:
The difference between the next term and 9 should be 4 + 1 = 5.
So, to find the missing term:
9 (last term) + 5 = 14.
Therefore, the correct answer is A) 14.