O-LEVEL Cheat Sheet 2026

The 30 highest-yield O-LEVEL facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. What is the name of the process where plants lose water through their leaves? → Transpiration
2. Carriage inwards is included in which financial statement section? → Trading account
3. What is Singapore's approach to water security? → The Four National Taps: local catchment, imported water, NEWater, and desalination
4. A 60 W bulb is used for 5 hours. How much energy does it consume? → 1080 kJ
5. What is the name of the process by which a solid changes directly into a gas? → Sublimation
6. What is the process by which water moves from an area of high water potential to low water potential through a semi-permeable membrane? → Osmosis
7. Which type of reaction releases heat energy to the surroundings? → Exothermic
8. What does 'inferring' mean in reading comprehension? → Making a logical conclusion from clues in the text
9. Who was Singapore's first Prime Minister? → Lee Kuan Yew
10. What type of reaction is: CH₄ + 2O₂ → CO₂ + 2H₂O? → Combustion
11. What is lg (logarithm base 10) of 1000? → 3
12. What is soil erosion? → The removal of topsoil by wind, water, or human activity
13. What is the function of the People's Association (PA) in Singapore? → To foster community bonding and social integration
14. What is the primary cause of coastal erosion? → Wave action, chemical weathering, and human activities
15. Accrued expenses are shown on the Balance Sheet as: → Current liabilities
16. In electrolysis, where does oxidation occur? → At the anode
17. What was Raffles' role in Singapore's colonial history? → He founded the British trading post in Singapore in 1819
18. The probability of an event is 0.35. What is the probability that the event does NOT occur? → 0.65
19. What colour is the precipitate formed when iron(III) ions react with sodium hydroxide? → Rust/brown
20. What does an ammeter measure? → Current
21. Which punctuation mark is used to introduce a list? → Colon
22. What is the derivative of y = 3x⁴ - 2x² + 5? → 12x³ - 4x
23. When a business purchases goods on credit from a supplier, which double entry is recorded? → Debit Purchases, Credit Creditors
24. What is the function of the diaphragm in breathing? → Contracts and relaxes to change chest volume
25. What is the function of an apostrophe in 'the teacher's book'? → To show possession
26. What is the oxidation state of oxygen in most compounds? → -2
27. What is the connotation of the word 'thrifty'? → Positive — it implies being careful with money
28. Which vitamin is produced by the skin when exposed to sunlight? → Vitamin D
29. Find the value of x: 5(x - 2) = 3x + 4 → 7
30. Which colour of visible light has the highest frequency? → Violet