- Let’s look at the rules first: two-level consequences for violations
- Approved models and options
- fx-50FH II vs fx-3650P II comparison
- Really useful built-in features
- Stored programmes: What can be done and where the lines are
- Paper 2 Quick Solution Techniques
- Paper 1 Check Calculation Strategy
- Five common operating mistakes
- Exam Day Checklist
Computers are the only computing tool allowed to be brought into the examination room for DSE Mathematics, but most candidates only use less than 20% of their capabilities. Taking advantage of built-in functions can save time, reduce calculation errors, and provide an independent way to verify calculations. But before we talk about any techniques, one more important thing must be dealt with: rules.
1. Let’s look at the rules first: two-level consequences for violations
The HKEAA issues a circular on the use of computers for the HKDSE every year, together with a "List of Approved Computer Models". The circular clearly states: Computers brought into the examination room Must be printed with "H.K.E.A.A. APPROVED" or "H.K.E.A. APPROVED" label, otherwise points may be deducted; And if the candidate brings Not allowed And computers that can gain unfair advantages by retrieving information,May be disqualified from the entire exam.
The difference between two levels of consequences
| Condition | as a result of |
|---|---|
| The computer model is on the approved list, but the machine does not have the APPROVED label (for example, the label has faded, or a non-local version has been purchased) | There is a chance of points being deducted |
| Bringing in an unauthorized computer that provides an unfair advantage in retrieving data | May be disqualified from the entire exam |
Other requirements from the HKEAA
- Label: The fuselage must be printed with "H.K.E.A.A. APPROVED" or "H.K.E.A. APPROVED". Those whose labels have faded should take them to the HKEAA to have them reprinted before the exam, or purchase a new machine.
- power supply: Dry batteries must be used as energy source.
- mute: No sound should be made during operation.
- show: Charts and text cannot be printed or displayed.
- body: Can't have any stickers or writing.
About the boundaries of stored programmes
This is the point that most students misunderstand. According to current rules, candidates Can Use pre-stored information on approved computers For calculation formulas (e.g. quadratic formula, solving simultaneous equations, trigonometric calculations), but No text data may be stored— Including text version of theorem description, formula explanation or answer tips. This is consistent with the requirement that "the computer cannot display Chinese sentences".
The judgment method is very simple: If the function of that piece of content is to "help you calculate", there is generally no problem; if the function is to "help you remember", it has crossed the line. It is a violation to store the words "sine formula" or its text description in it; it is a legal calculation aid to store the calculation formula for calculating the value of the sine formula.
Since the rules and lists are published every year, be sure to check the HKEAA's latest version for that year before taking the exam, and do not rely on previous years' information or anecdotal reports.
2. Approved models and selection
The HKEAA's approved list covers multiple brands (including A.MAX, ATABA/AURORA, BISTEC, BLT, CANON, CASIO, CITIZEN, HEWLETT-PACKARD, KARCE, SHARP, TEXAS INSTRUMENTS, TRULY, etc.) and hundreds of models. But in fact, DSE mathematics candidates focus on two programmable series of CASIO:fx-50FH／fx-50FH II and fx-3650P／fx-3650P II, both series are listed on the approved list.
The most common pitfall when purchasing is having similar model names but different machines. For example fx-50F II(without H) or fx-50F PLUS and fx-50FH II They are different models, and the non-local version may not be on the approved list, and will not be printed with the local APPROVED label - even if the functions appear to be the same, it is still illegal to bring it into the examination room. When the online purchase price is significantly lower than the market price, you should especially check the complete model number and label.
Purchase process
- Check the HKEAA first then Published list of approved computer models, confirm that the complete model (including letter suffix) is on the list.
- Check whether the red "H.K.E.A.A. APPROVED" label is printed on the fuselage.
- Purchase from regular retailers and keep the receipt for maintenance. The market reference price is approximately HK$220 to HK$350, depending on the model.
- Purchase Form 4 and start getting familiar with it, don't leave it until Form 6.
3. Comparison between fx-50FH II and fx-3650P II
| Compare items | CASIO fx-50FH II | CASIO fx-3650P II |
|---|---|---|
| Approved by HKEAA | Yes (requires APPROVED tag) | Yes (requires APPROVED tag) |
| type | programmable scientific computer | programmable scientific computer |
| Built-in formulas | There are about 23 built-in formulas that can be called directly | Fewer built-in formulas |
| programme capacity | About 680 bytes | You can enter the programme yourself |
| Relative strengths | Core’s common calculations and formula calls are the most convenient | Calculus-related functions are strong |
| more suitable | Students taking only Core | Taken simultaneously M1 or M2 students |
| Other functions | Base-n operation, logical operation, rounding settings | Complete statistics and calculation functions |
Which one should I buy?
- Read-onlyCore: fx-50FH II is generally more straightforward, and the built-in formulas are obviously helpful for common calculations.
- Concurrently with M1 or M2: Consider fx-3650P II, whose calculus-related functions are more useful for Extended Modules. Please see the subject selection considerations M1 M2 comparison.
- Have both: Many candidates will prepare a main machine and a backup machine. If the two models are different, please note that there are differences in the button positions and operation order (especially the processing of implicit multiplication). You should use both Form 1 models before the exam to avoid confusion.
The order of operations may be different for different models, especially implicit multiplications that omit the multiplication sign (e.g. 9÷3A This type of formula) may produce different results on different models. The safest approach is Always add parentheses, do not rely on the machine's default priority. This one habit can eliminate an entire class of calculation errors.
4. Really useful built-in functions
The following features are available on all approved programmable models, but Button locations and menu names vary by model— Please refer to the instruction manual of the model you have for actual operation, or have the instructor demonstrate it once in class.
CALC: core tool for substitution verification
usageEnter a calculation equation containing variables. After pressing CALC, the computer will prompt you to enter the values of each variable one by one, and the result will be obtained immediately.
Paper 2 ApplicationThe most effective way to simplify algebraic questions is to substitute the original formula and each option with the same set of special values. The answer is the same value. For example, simplify (x+y)² − 2xy, taking x=2, y=3, the original formula yields 25 − 12 = 13. Then substitute the same set of values into each option to find the option that also yields 13.
Avoid substituting 0 or 1 because multiple options may match at the same time. It is better to use small, asymmetric integers (such as 2 and 3) and double-check with a second set of values if necessary.
STO vs. RCL: Avoiding rounding errors
usageSTO stores the results in memory (A, B, C, D, X, Y, M, etc.), and RCL or ALPHA plus the corresponding letters can be retrieved and used.
Paper 1 ApplicationIn multi-step long questions, the intermediate results are completely stored in the memory and used in the next step to avoid accumulated errors due to rounding in the middle. This type of error is particularly likely to occur in geometry and trigonometry questions, and will cause the final answer to deviate from the acceptable scoring range.
CooperateANS will automatically save the last calculation result; directly enter the operation symbol during continuous calculation, and the machine will automatically connect to ANS.
Built-in formulas (fx-50FH II about 23)
usagefx-50FH II has about 23 built-in formulas that can be called directly, covering commonly used algebra and trigonometric calculations. Please refer to the machine manual for the actual list and calling keys.
applicationFor questions such as Paper 2 that only require correct numerical values, directly calling the built-in formula is much faster than hand calculation. But in Paper 1, you still have to write out the derivation steps - Paper 1 is scored according to the reasoning steps, and the answers alone are not enough to obtain full marks. See how to write the steps Paper 1 Strategy.
Statistics function
usageThe statistical mode can quickly find statistics such as average and standard deviation, and the processing of grouped data is also more reliable than manual calculation.
Must pay attentionBefore entering a new set of data Be sure to clear old statistics memory. Residual data is the most common source of errors in statistics questions, and the errors are very subtle - the results look reasonable, but in fact the data from the two questions are mixed together.
Fraction and decimal switching, angle mode
Score displayThe fraction and decimal switch keys switch between the two displays. Use fractional form when precise answers are needed to avoid errors caused by decimal truncation.
angle modeBefore calculating trigonometric functions, you must confirm that the unit of angle is Degree (DEG) rather than radians (RAD). The display should read D. This is the single setting that is most likely to cause the entire question to be wrong.
About the Base-n (carry conversion) function: fx-50FH II does have binary, octal, and hexadecimal conversion and logical operation functions, but these contents Not part of the course scope of DSE Mathematics Core, no need to spend time on this. If you see claims that "Base-n corresponds to DSE number system topics," you should be suspicious.
5. Stored programmes: what can be done and where are the boundaries?
Programmable models provide several programme storage locations (the programme capacity of fx-50FH/fx-50FH II is approximately 680 bytes). Within the scope of compliance, the following four types of programmes have the most practical value for DSE mathematics:
| programme type | enter | output | Corresponding topics |
|---|---|---|---|
| Synthesis of quadratic equations of one variable | Coefficients a, b, c | Two roots, discriminant, parabola vertex coordinates, axis of symmetry | Quadratic equations of one variable, quadratic functions and images, extreme value problems |
| Solving simultaneous equations | Coefficients of two (or three) equations | The value of each unknown number | Continuous equations, systems of linear equations, intersection points in coordinate geometry |
| Triangle Solving | Known combinations of sides and angles | The remaining sides, angles, and area of the triangle | Continuous triangle, two-dimensional and three-dimensional trigonometric problems |
| Sequences and Series | First term, tolerance or common ratio, number of terms | nth term, sum of first n terms, sum of infinite geometric series |
We don't post specific code on our pages. There are two reasons: First, the instruction writing method, variable upper limit and symbol input method are different between different models and different firmware versions. Copying the online programme code may not work on your machine, and you may even find it in the examination room after making the mistake; second, the programme must ensure that Does not contain any text data To ensure compliance, checking word for word is much more important than copying and pasting.
The correct approach is to input and test step by step according to the instructions of the model you have, or have the instructor demonstrate it once in class and then redo it yourself. our DSE Mathematics Course Will handle this part, including input, testing and compliance checks.
Three things you must do after entering the programme
- Test with examples with known answers: For example, if you test the quadratic equation with x² − 8x + 15 = 0, you should get 5 and 3. The test is completed only if it passes.
- Check if it contains text: Confirm item by item without any text description or prompts.
- Record the steps and practice them again regularly: The value of the programme lies in its ability to be called immediately on the spot. If you have to think about "which button to press" every time, it means nothing.
6. Quick Solution Techniques for Paper 2
Paper 2 has a total of 45 questions and a time limit of 75 minutes. Each question takes about 1 minute and 40 seconds on average, and No points will be deducted for wrong answers. These two conditions determine the role of the computer in Paper 2: it is not used to "solve problems", but to "quickly determine".
Four common techniques
- substitution method: Use CALC to substitute special values into the original formula and each option, and compare the values. Suitable for algebraic simplification and identity problems.
- Option validation: To solve equation-type questions, directly substitute the options back into the equation to check, which is usually faster than forward solving.
- Coordinate verification: For image or equation questions, substitute the coordinates of known points into each optional equation. The correct one should satisfy all known points.
- Elimination method and estimation: When it cannot be calculated directly, use a computer to estimate the range to eliminate obviously unreasonable options.
time discipline
- Complete the simple questions within 1 minute, and save the time for later stages.
- If a single question exceeds the scheduled time, it will be marked and skipped. Do not make a temporary judgment in the examination room whether it is worth continuing.
- Leave it for about 5 minutes at the end to check and make sure All questions have been answered— There is no negative score, leaving it blank is a pure loss.
See the full strategy DSE Mathematics Paper 2 Guide and time allocation.
7. Paper 1 Verification Strategy
Paper 1 has a full score of 105 points and a time of 135 minutes. It is divided into three parts: Part A (1), Part A (2) and Part B. Each part is worth 35 points. Because Volume One Score according to reasoning steps, the role of the computer here is completely different from that in Paper 2: it is a verification tool, not a problem-solving tool.
three principles
- The steps still have to be written by hand: Even if you use the built-in formula to directly get the answer, Paper 1 still has to write out the formula and substitution process. You will lose step points by just writing the answer.
- Intermediate results are stored in memory: Do not copy down the rounded intermediate value before entering it in the next step. Use STO to retain full precision.
- answer substitution test: After completion, substitute the answer back into the original equation or situation, and confirm that the value is reasonable (for example, the length should not be negative, and the probability must be between 0 and 1).
Check time allocation
It is recommended to reserve about 7 to 10 minutes within 135 minutes for final inspection, and give priority to checking two types of questions: easy questions in Part A (1) (the least worth losing points), and questions that have been marked when doing the questions. For step-by-step time suggestions, see Road map to reach the stars time allocation table.
8. Five common operating errors
| Mistake | as a result of | Treatment method |
|---|---|---|
| Angular mode error (Set to RAD instead of DEG) | The entire trigonometric calculation is wrong and the answer still looks like a reasonable number | Before opening the book, confirm that the display shows D; confirm again before each time you do the triangle question. |
| Statistics memory is not cleared | The mean and standard deviation are wrong, and the errors are so hidden that they are difficult to detect. | Clear statistical memory before entering new data each time |
| Depends on the order of operations of implicit multiplication | Different models have different results, calculation errors but the process seems correct. | Always use parentheses, do not rely on default precedence |
| Wrong mode or programme selection | The programme fails to operate or outputs meaningless results, wasting exam time | Confirm the current mode before calling the programme; fix the order of operations during daily practice |
| Overreliance on computers | Simple calculations become slower; mental arithmetic ability deteriorates | Set a boundary: use mental arithmetic for operations within two steps |
For other non-computer related point loss modes see Common missing points and miscalculated numbers in DSE mathematics.
9. Exam Day Checklist
- Model in HKEAA then In the published approved list (check the complete model including suffix)
- The fuselage has a clear "H.K.E.A.A. APPROVED" or "H.K.E.A. APPROVED" label printed on it that has not faded.
- There are no stickers, writing or markings on the body
- New dry batteries have been replaced and backup batteries or backup machines have been prepared.
- All pre-stored programmes have been tested and work and do not contain any text data.
- The angle mode is set to DEG and the display shows D
- Statistics memory cleared
- Display settings (fractions/decimals, decimal places) have been set according to custom
- All programme operation steps are so familiar that you don’t need to think about it.
Computers are subject to inspection by the invigilator on the day of the exam. Rather than begging for accommodation on the spot, it is better to complete the above list a week in advance - especially the label and list verification, which are the only aspects that may result in point deductions or disqualification.
Skills are only useful if they are combined with understanding
The computer can speed up calculations and verification, but it cannot judge for you which theorem to use, nor can it write out the reasoning steps for Paper 1 for you. In fact, students who rely too much on computers tend to lose more points on Section B questions—because those questions test derivation processes rather than numerical values.
our DSE maths tuition courses Make computer skills a part of test-taking training rather than an independent selling point: instructors will demonstrate the operation of each function, explain the mathematical principles behind it, define the scope of compliance, and train students to judge "when to use it and when to calculate by hand is faster." The course is taught by instructors who have taken the exam as self-taught students and obtained 5** in Core, M1, and M2. The teacher-student ratio is no more than 1:7 in small classes. Each class has about 12 to 14 people and is taught by two instructors.
- TOLL: Core 4 classes per month (1.5 hours each) HK$1,360; compulsory M1 or M2 (2 hours each) HK$1,600, see details Charge page.
- Class location: Room A, 9/F, Landmark City, 761 Nathan Road, Prince Edward, Kowloon (About 2 minutes’ walk from Exit C1 of MTR Prince Edward Station).
- WhatsApp/Phone: 9651 3910; Email: terrybgwan@gmail.com.
Students mainly come from Band 1 secondary schools in Kowloon district, including Diocesan Boys' School, Diocesan Girls' School, La Salle College, Maryknoll Convent School, Wah Yan College, Kowloon and Heep Yunn School. For the background of the centre, see About Math Insight, please see the instructor’s qualifications Maths Tutors.
Computer FAQ
Can DSE use calculator programmes?
Can use pre-stored For calculation programme, but the computer must be an approved model and have the APPROVED label printed on it, and the programme No text data may be stored (Include text version of theorem or hints). The rules are published every year and the latest version shall prevail.
What are the consequences of bringing the wrong computer?
Not having an APPROVED label may result in points being deducted; bringing in an unauthorized computer that can gain an unfair advantage by retrieving data may result in disqualification from the entire exam.
Is fx-50FH II better than fx-3650P II?
Both are on the approved list. fx-50FH II has about 23 built-in formulas and a programme capacity of about 680 bytes, which is more convenient for Core; fx-3650P II has strong calculus-related functions and is more suitable for concurrent studies M1 or M2 students.
Can I use cheaper models purchased online?
Not recommended.fx-50F II(no H) or fx-50F PLUS and fx-50FH II They are different models. The non-local version may not be on the approved list, nor will it be printed with the local APPROVED label. It is a violation to bring it into the examination room.
APPROVED label fade counting?
You should bring your computer to the HKEAA to have the label reprinted before the exam, or purchase a new computer. Don’t assume the proctor will be accommodating.
What should I do if maths ERROR is displayed?
Usually indicates that the operation is out of range or not mathematically sound (division by zero, square root of a negative number, wrong angle pattern, etc.). First check whether the input and angle units are correct; sometimes "no real number solution" itself is the answer to the question.
Is the Base-n feature useful for DSE?
Carry system conversion and logical operations are not within the scope of the DSE Mathematics Core curriculum, and there is no need to spend time practicing for this.
When did you start practicing computer skills?
It is recommended that Form 4 purchase an approved model and become familiar with it simultaneously. The value of skill lies in proficiency - thinking of steps on the spot means you don't have this skill.
Do I need to prepare a backup computer?
Preparation is recommended. The backup machine must also be of the approved model and have the APPROVED label printed on it; if it is different from the main machine model, attention must be paid to the differences in the operation sequence and button positions.