Olympiad practice for Class 5

Try 10 real Class 5 questions

Straight from the PrepMojo question bank, written to the pattern of the SOF papers. Have a go, then open the answer.

1. Question 1 · Maths

   Which of these numbers is built from the fewest DIFFERENT prime factors?

   1. A.1331
   2. B.1944
   3. C.294
   4. D.1638
   Show answer

   Answer: A. 1331

   Break each number down into primes: 1944 = 2 x 2 x 2 x 3 x 3 x 3 x 3 x 3 (2 different); 1638 = 2 x 3 x 3 x 7 x 13 (4 different); 294 = 2 x 3 x 7 x 7 (3 different); 1331 = 11 x 11 x 11 (1 different). So the answer is 1331. Count how many DIFFERENT primes appear, not how many factors there are altogether - a number can be built from a single prime used eight times over.

2. Question 2 · Maths

   Which of these Roman numerals is written correctly?

   1. A.DCCCCXXXXVIIII
   2. B.VVVV
   3. C.CDXCIX
   4. D.IXXLCM
   Show answer

   Answer: C. CDXCIX

   CDXCIX is the only one that keeps every rule. It reads 400 + 90 + 9 = 499. The rules are: I, X, C and M may be repeated at most three times; V, L and D are never repeated and never taken away; I may only be taken from V and X, X only from L and C, and C only from D and M; and the symbols run from the largest value to the smallest.

3. Question 3 · Maths

   What kind of angle measures 30°?

   1. A.obtuse
   2. B.right
   3. C.acute
   4. D.straight
   Show answer

   Answer: C. acute

   An angle of 30° is acute. Acute is less than 90°, a right angle is exactly 90°, obtuse is between 90° and 180°, and straight is exactly 180°.

4. Question 4 · Science

   In a food chain the arrow means 'is eaten by'. Which of these food chains is incorrect?

   1. A.Grass → Lizard → Insect
   2. B.Rose plant → Aphid → Ladybird
   3. C.Leaves → Snail → Frog
   4. D.Leaves → Caterpillar → Sparrow → Hawk
   Show answer

   Answer: A. Grass → Lizard → Insect

   Energy travels along the arrows, so a food chain must begin with the plant. The chain that is wrong has swapped the last two links; written properly it runs Grass → Insect → Lizard.

5. Question 5 · Science

   Which of these is mainly giving out heat energy and is used up faster than nature can ever replace it?

   1. A.Natural gas burned in a stove
   2. B.A disposable torch battery
   3. C.Heat from deep inside the Earth
   4. D.Firewood burned for cooking
   Show answer

   Answer: A. Natural gas burned in a stove

   Only the natural gas burned in a stove fits both clues: it is mainly giving out heat energy and it is used up faster than nature can ever replace it. The firewood burned for cooking is close, but it is renewable.

6. Question 6 · English

   What does the phrasal verb 'Turn down' mean?

   1. A.to raise the volume or to arrive somewhere
   2. B.to refuse an offer, or to lower the volume
   3. C.to become or transform into something
   4. D.to result in a particular way
   Show answer

   Answer: B. to refuse an offer, or to lower the volume

   'Turn down' means to refuse an offer, or to lower the volume. To raise the volume or to arrive somewhere is often guessed instead, because 'turn up' means this - the opposite idea.

7. Question 7 · English

   Someone says: "I am so sorry to hear that." What is the speaker doing?

   1. A.Agreeing with someone
   2. B.Refusing politely
   3. C.Showing sympathy
   4. D.Apologising
   Show answer

   Answer: C. Showing sympathy

   Saying 'I am so sorry to hear that.' is showing sympathy - it is not apologising, because the sorry is for the hearer's trouble, not for anything the speaker did.

8. Question 8 · Logical Reasoning

   Which letter lies exactly midway between G and U in the English alphabet?

   1. A.M
   2. B.O
   3. C.N
   4. D.J
   Show answer

   Answer: C. N

   G and U are 14 letters apart, so the middle lies 7 letters after G: N.

9. Question 9 · Logical Reasoning

   Today is Saturday. What day of the week will it be after 11 days?

   1. A.Sunday
   2. B.Wednesday
   3. C.Tuesday
   4. D.Thursday
   Show answer

   Answer: B. Wednesday

   Every 7 days the week repeats: 1 full week lands on Saturday again, then 4 more days on - Wednesday. The count starts with tomorrow, never with today itself.

10. Question 10 · Computers

    Railway booking counters in stations all over the country work from the same list of seats, so a berth sold in one town cannot be sold again in another. Which kind of network is this?

    1. A.WAN
    2. B.LAN
    3. C.MAN
    4. D.PAN
    Show answer

    Answer: A. WAN

    Ask how far the network has to reach, not what it is used for. Here it reaches every state in the country, and a wide area network covers a whole country or more. Everything else on the list is built for a different distance.

What the Class 5 SOF papers cover

As published by the Science Olympiad Foundation for Class 5.

All 61 olympiads open to Class 5

Grouped by the body that runs them. Each links to its exam pattern, fee and full syllabus.

Questions parents ask about Class 5

Which olympiads can a Class 5 student take?

61 olympiads from 11 organising bodies admit Class 5, including the SOF International Mathematics Olympiad (IMO), the SOF International Science Olympiad (NSO, now ISO) and the SOF International English Olympiad (IEO). The full list, with exam windows, is on this page.

Is PrepMojo free for Class 5?

Yes. Every child gets 10 practice questions a day free, forever, with no card needed, plus one free mock paper every 60 days. PrepMojo Plus adds unlimited daily practice, unlimited SOF-pattern mock papers and 100 Mojo AI tutor doubts a month, from ₹299. Till 30 Nov 2026, every child has Plus at no cost as part of our Navratri and Diwali Offer.

How long is the Class 5 IMO paper?

The SOF IMO paper for Class 5 has 50 questions and runs for 60 minutes. Level 1 is held Oct-Dec.

Which subjects does PrepMojo cover for Class 5?

Maths, Science, English, Logical Reasoning and Computers, following the syllabus each olympiad's organising body publishes. Practice works in the app on iPhone and Android and in any web browser.