CA Foundation Jan 2027 maths important questions: 14 repeats
The CA Foundation maths important questions for January 2027 are the question types ICAI set in its own three 2026 Quantitative Aptitude papers, and above all the ones it asked a second time within the same year. In September 2026, ICAI repeated May's limit question word for word, January's family-tree puzzle with only the options reshuffled, and twelve more ideas with new numbers or a new twist. Below is every chapter's set of question types with the question numbers, the fourteen repeats, and three questions worked from ICAI's answer key.
Paper 3 is 100 MCQs of one mark each in 2 hours, from 2 PM to 4 PM, with no reading time. ICAI's January 2027 schedule (PDF) (opens in a new tab) puts the four Foundation papers on 3, 5, 7 and 9 January 2027. The September 2026 booklet's instructions state the marking: one mark for a right answer, a quarter of a mark off for a wrong one, zero for a blank, and more than one circle darkened counts as wrong.
Where these important questions come from
We read all 300 questions of ICAI's three 2026 Paper 3s:
| Attempt | ICAI file | Answers |
|---|---|---|
| January 2026 | Suggested answers (PDF) (opens in a new tab), Paper 3 from page 71 | ICAI's answer key |
| May 2026 | Suggested answers (PDF) (opens in a new tab), Paper 3 from page 80 | ICAI's answer key |
| September 2026 | Question paper (PDF) (opens in a new tab) | Ours |
On 23 October 2026, ICAI's Foundation suggested answers page (opens in a new tab) on icai.org still listed May 2026 as the newest, so any September 2026 answer below is our own working. Grouping a question under a type is also our reading.
How many questions each chapter got is in our CA Foundation Jan 2027 Maths mock test post, with the eight types that came in all three papers. This post goes one level down: the actual questions.
CA Foundation maths important questions, chapter by chapter
The types below are what ICAI set in 2026. Question numbers are January / May / September, so you can open ICAI's papers and practise the real ones.
| Chapter | Question types ICAI set | Where (J / M / S) |
|---|---|---|
| 1. Ratio, indices, logarithms | Ratio after adding people; income–expenditure ratio; log of a product; indices simplification | J49–50, J53 / M54–58 / S51–54 |
| 2. Equations | Equation with given roots; ages; simultaneous and three-variable systems | J1, J51–52 / M1, M4 / S2–3, S55 |
| 3. Linear inequalities | Solve an inequality; write the constraints; is the feasible region bounded or unbounded? | J2, J4, J56 / M2–3, M5 / S56 |
| 4. Mathematics of finance | CI vs SI difference; EMI from P(n, i); sinking fund; depreciation; NPV; perpetuity; CAGR | J5–11, J54–55, J57–61 / M6–11, M59–65, M67 / S4–11, S58–63 |
| 5. Permutations and combinations | Numbers formed from digits; people who must sit together or apart; selections | J62–65 / M12, M66, M68–69 / S12–15 |
| 6. Sequence and series | Infinite GP; nth term or sum of an AP; terms of a GP | J12–14, J68 / M13–16 / S16, S64–65, S67 |
| 7. Sets, relations, functions, limits | Composite function f(f(x)); equivalence relation; limit at infinity; Venn counts | J17, J66–67, J69 / M70–73 / S17, S19, S66, S68 |
| 8. Calculus | Cost and revenue: AC = MC, minimum AC, maximum revenue, cost from MC; dy/dx; a definite integral | J15–16, J18, J72 / M17–20 / S18, S20, S69, S71 |
| 9. Series, coding, odd man out | Next or wrong term; letter shift; number codes | J19, J21, J70–71, J73 / M21, M74–75, M77–78 / S21, S23, S70, S72–73 |
| 10. Direction tests | Final direction; distance by Pythagoras | J20, J22, J74, J76–77 / M22–25, M76 / S22, S24, S74–76 |
| 11. Seating arrangements | Row, circle or table puzzle | J23–26, J75 / M26, M79–82 / S25–27, S77, S79 |
| 12. Blood relations | Family tree; coded symbols; "only son of my mother" | J29, J78–81 / M27–31 / S28–30, S78, S80 |
| 13. Data and sampling | Parts of a table; ogive; curve shapes; naming the sampling method; standard error | J27–28, J30–33, J82–84 / M32–33, M36–37, M83–87 / S31–32, S38, S81–84, S86–87 |
| 14. Central tendency and dispersion | Combined mean or SD; mean, median, mode relation; change of origin and scale; quartile deviation | J34–38, J85–89 / M34–35, M38–39, M42, M88–92 / S33–37, S39, S85, S88–91 |
| 15. Probability | Two dice; cards; at least one succeeds; conditional; Bayes | J39–41, J90–92 / M40–41, M43, M93, M95–96 / S40–43, S92–94 |
| 16. Theoretical distributions | Binomial n and p from mean and variance; Poisson; normal quartiles | J44, J93–96 / M44–45, M47–48, M94 / S95–97 |
| 17. Correlation and regression | Means from two regression lines; Spearman; r from coefficients | J42–43, J45, J97, J99 / M46, M49, M97, M99–100 / S44–47, S99 |
| 18. Index numbers | Time reversal, factor reversal, circular test; Fisher; base shifting and splicing | J46–48, J98, J100 / M50–53, M98 / S48–50, S98, S100 |
What stands out: every chapter's types are short. Most need one formula and two or three steps; the long ones (combined standard deviation, Bayes, NPV with a table, Fisher from four commodities) are few, and you can leave them for the end. Keep the CA Foundation Maths formula sheet open while you practise them.
CA Foundation maths most important questions: 14 that ICAI asked again
These came twice in 2026, often with the same wording and only new numbers. If January 2027 follows the same habit, they are the safest marks in the paper.
| # | Question | First asked (ICAI's key) | Again |
|---|---|---|---|
| 1 | Limit as x → ∞ of (x² + 2x + 2)/(3x² + x + 1) | May Q73 (1/3) | Sep Q17, word for word |
| 2 | A is the son of C; C and Q are sisters; Z is Q's mother; P is Z's son | Jan Q78 (P is A's maternal uncle) | Sep Q30, word for word |
| 3 | Is "a − b divisible by k" an equivalence relation? | May Q71, k = 5 (equivalence) | Sep Q66, k = 3 |
| 4 | f(f(1/x)) for f(x) = 1 ± 1/x | Jan Q66, 1 + 1/x ((x + 2)/(x + 1)) | Sep Q19, 1 − 1/x |
| 5 | Range of y when x and y are linearly related | Jan Q35 (40) | Sep Q39 |
| 6 | Mean deviation of y from a linear relation | Jan Q89 | Sep Q35 |
| 7 | Mode or median from the other two averages | Jan Q87 (mode 33) | Sep Q34 |
| 8 | Standard deviation of two groups combined | Jan Q38 (5.95) | Sep Q33 |
| 9 | An "only son of my mother" riddle | Jan Q80, "son of the only son of my mother" (father) | Sep Q80, "only son of my mother's mother" |
| 10 | Blood relations written as +, −, × symbols | Jan Q79 (uncle) | Sep Q78 |
| 11 | Shape of a frequency curve from its description | Jan Q83 (bell-shaped) | Sep Q83, the J-shaped curve (our answer) |
| 12 | Sum from the difference between CI and SI | May Q6 (₹39,975) | Sep Q4 |
| 13 | dy/dx when x and y are given in terms of m | May Q17 (−1/m⁴) | Sep Q18 |
| 14 | dy/dx of an implicit function | May Q19 | Sep Q20 |
Two more patterns ran through all three papers but with fresh wording: a feasible-region question (Jan Q56, May Q2, Sep Q56) and a sampling-method question (Jan Q27 and May Q85 describe a survey and ask which method it is; Sep Q38 asks when stratified sampling is advisable).
Three CA Foundation maths questions, worked from ICAI's key
1. A limit ICAI set twice (May 2026 Q73, September 2026 Q17)
Question: Evaluate the limit, as x → ∞, of (x² + 2x + 2)/(3x² + x + 1).
- Top and bottom have the same highest power, x².
- Divide both by x²: (1 + 2/x + 2/x²)/(3 + 1/x + 1/x²). As x → ∞ every term with x below it goes to 0.
- Limit = 1/3. ICAI's May key is option (A), 1/3. In September the same 1/3 was option (D).
The habit: when the powers match, the answer is the ratio of the leading coefficients. Ten seconds.
2. The family tree that came back (January 2026 Q78, September 2026 Q30)
Question: A is the son of C; C and Q are sisters; Z is the mother of Q, and P is the son of Z. Which statement is true?
- C and Q are sisters, so Z is C's mother too.
- P is Z's son, so P is C's brother.
- A is C's son, so P is A's mother's brother: P is the maternal uncle of A. That is ICAI's January key, option (A). In September it was option (C).
The trap: "P and A are cousins" sits right beside it. Draw the three generations as a tiny tree before you read the options.
3. Range from a linear relation (January 2026 Q35)
Question: x and y are related by 5x − 3y = 15, and the range of x is 24. Find the range of y.
- Write y in terms of x: y = (5x − 15)/3, so y moves 5/3 times as much as x.
- Range of y = 5/3 × 24 = 40. ICAI's key is option (D), 40.
- September's Q39 is the same idea: 4x + 6y = 20 gives y = (20 − 4x)/6, so the range of y is 4/6 × 30 = 20 (our working).
The rule: a constant added changes nothing; the multiplier counts without its sign, because range and standard deviation are never negative.
Most important chapters for CA Foundation maths
Mathematics of finance is the most important chapter: it was the largest single chapter in all three 2026 papers. Central tendency and dispersion led Statistics each time, and the four Logical Reasoning chapters were always level with one another. ICAI's syllabus fixes the parts at Business Mathematics 40, Logical Reasoning 20 and Statistics 40 (Paper 3 syllabus, PDF (opens in a new tab)).
The chapter-wise counts are in the CA Foundation Maths mock test post, and our CA Foundation Jan 2027 chapter wise weightage sets Paper 3 beside the other three papers.
One warning: some guides online list syllogism and logical connectives under Logical Reasoning. Those are not chapters in ICAI's current syllabus, which has four: number series, coding and odd man out; direction tests; seating arrangements; and blood relations.
Is CA Foundation maths difficult?
It is fast more than it is hard. Most 2026 questions needed one formula and two or three steps, and Logical Reasoning (20 marks) needs no school maths at all. What makes Paper 3 feel difficult is the clock: 100 questions in 120 minutes, no reading time, and a quarter mark lost for each wrong answer.
ICAI's own keys show how carefully you must read: May 2026 notes that "None of the options are correct" for Q41 and Q69. If an answer isn't there after one honest re-check, move on.
For a non-maths student, the order that works: Logical Reasoning first, then Statistics (mostly one-formula questions), then mathematics of finance with a basic calculator. The Maths mock test post has the calculator habits and a 2-hour plan.
CA Foundation maths important questions PDF and extra questions, free
ICAI's own files are the best PDF of important questions, and they are free.
- The three 2026 papers linked above, each in 2 hours. Older papers are on our CA Foundation past year question papers page.
- Extra questions: each chapter of ICAI's study material ends with exercises, and several Business Mathematics and Statistics chapters add an "Additional Question Bank". For January 2027, Paper 3 uses the August 2024 edition (Reprint August 2025 onwards), with no RTP listed for it (ICAI notice, PDF (opens in a new tab)). It is on our CA Foundation study material page.
- ICAI's MTPs: ICAI announced the January 2027 Foundation MTPs on 21 October 2026. Paper 3 is on 7 December 2026 (Series I) and 18 December 2026 (Series II), 2 PM to 4 PM, with papers on boslive.icai.org and answer keys within 48 hours (ICAI announcement, PDF (opens in a new tab)). Earlier MTPs are on our CA Foundation MTP page.
Write the important questions in a full paper
Knowing the types is half the job; doing them inside 120 minutes is the other half. Our CA Foundation Quantitative Aptitude mock tests are full-syllabus Paper 3s on ICAI's current pattern, scored the way ICAI scores it. Every attempt gets new papers with a fresh set of questions, set at the real ICAI exam standard.
You write the option letters by hand, scan your pages and upload one PDF. Your checked copy comes back within 24 hours with the reason for every mark lost, and the solution opens as soon as you buy. Before buying, you can read preview pages of Mock Test 1. When to sit each mock before January is in our CA Foundation Jan 2027 mock test plan.
Frequently asked questions
Are CA Foundation maths questions repeated?
Yes, within 2026 at least. In 2026, ICAI asked May's limit question again in September word for word, and January's family-tree question again with the options reshuffled. Twelve more ideas came back with new numbers or a new twist. Practise ICAI's three 2026 papers before anything else.
Which chapters are most important in CA Foundation maths?
Mathematics of finance, the largest single chapter in every 2026 paper, then central tendency and dispersion. Logical Reasoning's four chapters are the quickest marks to secure.
Is maths compulsory in CA Foundation?
Yes. Paper 3, Quantitative Aptitude, is one of the four Foundation papers, with Business Mathematics, Logical Reasoning and Statistics all inside it. There is no option to skip it.
Are there any CA Foundation maths tricks that really work?
Three that ICAI's 2026 questions reward: for a limit at infinity with equal powers, take the ratio of the leading coefficients; for range or standard deviation of a related variable, use only the multiplier, without its sign; and in a family-tree question, draw the generations before reading the options.
Is there negative marking in CA Foundation maths?
Yes. A quarter of a mark comes off for each wrong answer, a blank scores zero, and darkening more than one circle for a question counts as wrong, as the September 2026 booklet states.
Your next step
Take ICAI's September 2026 Paper 3 and do only the fourteen repeats and the chapter types above, against the clock. Every miss tells you which formula to fix. Then move to full CA mock tests under exam conditions: our CA Foundation test series covers all four papers, and the CA test series home page has every level. The sister posts on CA Foundation accounts important questions and economics important questions do the same for Papers 1 and 4.