Most calculator advice lists every menu on the TI-36X Pro. That is not how exam time is lost. It is lost retyping a rounded intermediate, missing one parenthesis in a long expression, or leaving the calculator in radians. This guide counts which calculator skills our FE and PE practice questions actually use, ranks them for each exam, and gives exact keystrokes for the ones worth drilling.
Still choosing a calculator? The FE exam calculator guide compares the approved models and walks through the TI-36X Pro solver, matrix and statistics menus in detail. This page is about priorities: which skills to practice first, and why they save time.
Sources. Keystrokes follow the TI-36X Pro guidebook; page numbers are cited with each skill. Exam-room rules follow the May 2026 NCEES Examinee Guide. Every worked answer below was recomputed independently.
Which calculator skills do FE and PE questions use most?
Every question in our practice banks carries tags for the calculator work its worked solution needs. We counted those tags across all 12 exams on September 30, 2026: 8,513 questions served across the six FE exams and 3,690 across the six PE exams. The table gives the average share of each exam's questions that use a skill, with the lowest and highest exam in parentheses.
| Calculator skill | FE exams: average (range) | PE exams: average (range) |
|---|---|---|
| No calculator needed (conceptual) | 29.2% (25.6–31.8) | 30.7% (24.8–47.2) |
| Multi-step expression entry | 46.0% (36.7–53.0) | 53.4% (40.6–70.0) |
| Powers and roots | 20.0% (15.4–24.9) | 16.8% (10.0–23.5) |
| Table work and iteration | 6.8% (3.9–10.1) | 8.3% (0.1–16.6) |
| Stored values (sto→, recall) | 7.0% (4.4–11.6) | 7.1% (0.0–13.9) |
| Unit conversion | 5.1% (2.7–6.3) | 5.9% (1.7–18.7) |
| Scientific notation (EE) | 4.2% (2.2–6.8) | 4.5% (0.3–17.4) |
| Logs, exponentials and dB | 4.4% (2.4–6.7) | 2.8% (0.5–8.5) |
| Statistics and probability | 4.2% (3.1–5.1) | 0.1% (0.0–0.4) |
| Numeric integral or derivative | 3.3% (2.2–4.0) | 0.3% (0.0–0.7) |
| Trig and inverse trig | 2.2% (0.8–3.6) | 2.1% (0.0–5.2) |
| Numeric, polynomial or system solver | 1.1% (0.9–1.3) | 0.1% (0.0–0.5) |
| Matrices | 1.0% (0.0–2.7) | 0.3% (0.0–0.9) |
| Base conversion (base n) | 0.4% (0.0–2.3) | 0.5% (0.0–2.7) |
| Complex numbers | 0.3% (0.0–2.0) | 0.4% (0.0–2.5) |
How counted: served practice questions per exam, including the shared math, statistics, ethics and economics questions routed to each FE exam. A question can carry several tags, so rows overlap and do not sum to 100%. “Table work” covers solutions that read or iterate through a supplied table. Tags describe the solution path we authored, not official NCEES frequencies or measured candidate behavior. Five small tags (hyperbolic functions, physical constants, time value of money, formula substitution and algebra) each stay under 1% on every exam and are omitted.
Three findings change how to spend practice time:
- The fundamentals dominate. Multi-step entry and powers or roots appear in far more questions than any menu. If those are slow or error-prone, no solver will make up the difference.
- Solvers and matrices are rare. They are worth learning, because they turn a long algebra problem into a short one, but they are about 1% of FE questions and almost absent from PE questions in our banks.
- PE exams drop the FE menus. Statistics, numeric calculus and solvers nearly vanish on the PE side, while stored values and table work matter as much as or more than on the FE.
What should you practice first for your exam?
Every exam starts with expression entry, so the table lists the next skills in order of their share of that exam's questions. Practice down the list until each skill feels routine.
| Exam | Expression entry | Practice next, in order |
|---|---|---|
| FE Civil | 42.2% | Powers/roots 20.7%; stored values 11.6%; table work 5.8%; unit conversion 5.8%; trig 3.6%; statistics 3.6% |
| FE Electrical and Computer | 36.7% | Powers/roots 18.7%; table work 10.1%; stored values 7.5%; EE 6.8%; logs/dB 5.4%; base conversion 2.3%; complex 2.0% |
| FE Mechanical | 48.4% | Powers/roots 24.1%; stored values 7.7%; unit conversion 5.6%; table work 5.5%; statistics 4.6%; numeric calculus 4.0% |
| FE Chemical | 49.9% | Powers/roots 15.4%; logs/exponentials 6.7%; table work 6.3%; unit conversion 6.3%; stored values 5.4%; EE 4.2% |
| FE Environmental | 46.1% | Powers/roots 16.5%; unit conversion 5.7%; logs/exponentials 5.4%; stored values 5.2%; statistics 5.1%; numeric calculus 3.9% |
| FE Other Disciplines | 53.0% | Powers/roots 24.9%; table work 9.2%; unit conversion 4.5%; stored values 4.4%; statistics 4.4%; logs 4.0% |
| PE Civil: Transportation | 58.0% | Table work 16.6%; powers/roots 10.0%; stored values 5.7%; trig 3.1% |
| PE Civil: Structural | 47.8% | Powers/roots 19.4%; stored values 11.4%; unit conversion 4.3%; trig 2.2% |
| PE Civil: Water Resources & Environmental | 49.7% | Powers/roots 22.2%; stored values 9.8%; table work 7.1%; unit conversion 6.5%; logs 4.2% |
| PE Electrical: Power | 54.1% | Powers/roots 23.5%; stored values 13.9%; table work 9.8%; trig 5.2%; complex 2.5% |
| PE Computer Engineering | 40.6% | Table work 14.0%; powers/roots 10.7%; EE 3.8%; base conversion 2.7%; logs 2.2% |
| PE Electronics, Controls, and Communications | 70.0% | Unit conversion 18.7%; EE 17.4%; powers/roots 14.8%; logs/dB 8.5% |
PE Computer Engineering stands out: 47.2% of its questions need no calculator at all, the most of any exam we cover. Its calculator time goes mostly to reading supplied tables and converting between number bases.
Why do these skills save the most time?
The FE gives you 110 questions in 5 hours 20 minutes of testing time, a little under 3 minutes each. PE exams allow about 6 minutes per question, but those minutes go to longer calculation chains and reference searches. Either way, calculator time is time taken from reading the problem and finding the right equation.
The skills at the top of the table share one property: they reduce what you type and what you retype.
- Expression entry: entering a formula once, in one line, with the right parentheses, replaces three or four separate calculations whose intermediate results you would otherwise write down and key in again.
- Stored values: recalling a stored intermediate takes one or two key presses. Retyping it takes as many presses as it has digits, and retyping a rounded copy can move a close answer choice.
- Table work: the function table evaluates one expression at many inputs, so a trial-and-error search is one definition plus a scroll instead of a retyped expression per trial.
- Mode and notation habits: a wrong angle mode or a doubled power of ten produces a confident wrong answer. Catching that costs a full re-solve; preventing it costs a glance at the status line.
We do not quote a seconds-per-skill figure because we have not timed candidates on these operations. Time yourself on the worked examples below, then repeat them until the keystrokes need no thought.
Keystrokes for the core skills
How to read the steps: 2nd followed by a name in brackets, such as 2nd [recall], means press 2nd and then the key with that label printed above it. The variable key, labeled x yzt abcd and written x below, is multi-tap: one press gives x, two give y, and so on through x, y, z, t, a, b, c, d (guidebook pp. 8, 31). Arrow keys are written → and ↓. Examples assume the default MathPrint mode.
1. Multi-step expression entry and the last answer
Where it shows up: nearly half of all questions on every exam. Equivalent resistance, flow rates, stresses, efficiencies and economic factors are all a single formula entered in one pass.
Try it: 220 Ω and 330 Ω in parallel, in series with 100 Ω; then the current from 12 V
1 ÷ ( 1 ÷ 220 + 1 ÷ 330 ) + 100 enter
Expect 232 Ω. Now find the current without retyping 232:
12 ÷ 2nd [answer] enter
Expect 0.0517 A (51.7 mA). When the next step starts with the previous result, just press the operator: × 12 enter gives ans×12 (guidebook p. 10).
Common mistake: dropping the parentheses. Entering 1 ÷ 1 ÷ 220 + 1 ÷ 330 + 100 returns about 100.0076, a plausible-looking number that is wrong. Read the whole entry line before pressing enter.
The ↔ ≈ answer-toggle key switches a result between exact and decimal forms and shows the stored full-precision value (p. 10). Use it when an answer choice differs only in the third significant figure.
2. Powers and roots
Where it shows up: about a fifth of FE questions and up to 23.5% of a PE exam: pipe areas, RMS values, kinetic energy, Hazen-Williams and Manning exponents, and power in resistive loads.
Try it: Hazen-Williams head loss, SI form hf = 10.67 L Q1.852 / (C1.852 D4.87)
L = 500 m, Q = 0.03 m3/s, C = 120, D = 0.2 m. Use the power key x□ and press → to leave each exponent (p. 17):
10.67 × 500 × .03 x□ 1.852 → ÷ ( 120 x□ 1.852 → × .2 x□ 4.87 → ) enter
Expect hf ≈ 2.88 m. For a square root, use 2nd [√]; for an nth root, 2nd [n√] (p. 17). x² squares the value just before it.
Common mistake: forgetting → after an exponent. Everything you type next stays inside the superscript, so the rest of the formula becomes part of the power. A second trap: negation ranks below powers (p. 11), so (-) 3 x² gives −9. Enter (−3)² with parentheses when the sign belongs inside.
3. Stored values: sto→ and recall
Where it shows up: 7% of questions on average, and more where one intermediate feeds several checks: 13.9% of PE Power, 11.6% of FE Civil and 11.4% of PE Structural questions.
Try it: compare two factored load combinations from D = 12.5 kip and L = 18.75 kip
Store each load once (p. 31):
12.5 sto→ x enter 18.75 sto→ x x enter
The first stores 12.5 in x; the second press of the variable key selects y. Now each combination uses the names, not the digits. Pressing the variable key inserts the stored value into the entry (p. 32):
1.2 × x + 1.6 × x x enter 1.4 × x enter
Expect 45 kip for 1.2D + 1.6L and 17.5 kip for 1.4D, so 1.2D + 1.6L governs. 2nd [recall] shows all eight variables and their values if you lose track (p. 32).
Common mistake: a stale value from an earlier problem. Memory survives turning the calculator off (p. 3), and features such as the solvers use the values you store (p. 31). Clear them with 2nd [clear var] 1 at the start of a practice set (p. 32).
The time saving grows with the intermediate. A computed value such as a section modulus or a per-unit impedance may carry ten digits; storing it keeps full precision and replaces ten presses with one or two.
4. Table work and iteration
Where it shows up: 16.6% of PE Transportation, 14.0% of PE Computer Engineering and 10.1% of FE Electrical and Computer questions. Most of these supply a table (a timing summary, a pay estimate, a cost schedule) and ask you to carry values through it, which is expression entry plus stored values. The calculator's own table key helps when you must evaluate one expression at several inputs or bracket a root by trial.
Try it: find the subcritical depth where specific energy E = 1.5 m, with q = 2 m2/s
Set f(x) = x + q2/(2gx2) − E with g = 9.81 m/s2 and look for a sign change (pp. 49–51):
- Press table 2 (Edit function) and clear.
- Enter the function:
x + 4 ÷ ( 2 × 9.81 × x x² ) − 1.5 enter
- In TABLE SETUP, type Start 1 ↓, Step .1 ↓, leave Auto selected, ↓ to CALC and press enter.
- Scroll down: f(1.3) ≈ −0.0794 and f(1.4) ≈ +0.0040. The root lies between them.
Interpolate on the home screen: 1.3 + 0.1 × 0.0794 ÷ (0.0794 + 0.0040) ≈ 1.395 m. The exact root is 1.3953 m. A table started at 0.4 would also show the supercritical root near 0.438 m, so check which depth the question asks for.
Common mistake: a step that is too coarse. If two roots fall between table rows, the signs match and no crossing appears. Shrink the step near a suspected turning point. To evaluate the function at a single input, press 2nd [quit], table 1 to paste f(, then type the input, ) and enter (p. 51).
5. Unit conversion
Where it shows up: about 5% of questions on average and 18.7% of PE ECC questions, the highest of any skill outside expression entry on that exam.
Try it: 500 gpm in ft3/s
Chain the factors in one line, dividing by 7.48052 gal/ft3 and 60 s/min:
500 ÷ 7.48052 ÷ 60 enter
Expect 1.114 ft3/s. Write the units beside each factor on paper so they cancel visibly.
The built-in menu, 2nd [convert], holds 20 conversions (40 counting both directions) in five groups: English-Metric, Temperature, Speed and Length, Pressure, and Power and Energy (pp. 66–67). It covers ft▸m, °F▸°C and J▸kWh, but not gpm, MGD or most flow units, so factor chains remain the main exam skill.
Common mistake: using a length factor for an area or volume. 1 ft = 0.3048 m, so 1 ft2 = 0.30482 m2 and 1 ft3 = 0.30483 m3.
6. Scientific notation with EE
Where it shows up: 4–7% of most FE exams and 17.4% of PE ECC: capacitances, currents, noise powers, diffusion coefficients and rate constants.
Try it: thermal noise power kTB at T = 290 K over B = 1 MHz
1.380649 EE (-) 23 × 290 × 1 EE 6 enter
Expect 4.004 × 10−15 W. EE enters the power of ten as part of the number, so 2 EE 5 is 200000 (p. 16). The mode screen’s NORM, SCI and ENG settings change only how results are displayed, not the stored precision (pp. 5–6).
Common mistake: typing × 10 before EE, which multiplies by ten twice, or using the subtraction key instead of (-) for a negative exponent.
7. Logarithms, exponentials and dB
Where it shows up: 4.4% of FE questions on average, most in FE Chemical (6.7%), and 8.5% of PE ECC. pH, first-order decay, decibels and link budgets all depend on choosing the right base.
Try it: the noise power above in dBm, then a decay time
The ln log key is multi-tap: one press gives ln, two give log (p. 27). Right after the kTB result:
10 × ln log ln log 2nd [answer] ÷ 1 EE (-) 3 ) enter
Expect −114.0 dBm. For the time for a first-order concentration to fall from 100 to 20 mg/L with k = 0.25 d−1, t = ln(100/20) / k:
ln log 100 ÷ 20 ) ÷ .25 enter
Expect 6.44 days. The separate e□ 10□ key works the same way: one press for ex, two for 10x (p. 27).
Common mistake: the wrong base, or a missing ). ln( and log( open a parenthesis you must close; without it, ÷ 0.25 lands inside the log. For pH at [H+] = 0.001, −ln gives 6.91 while the correct −log gives 3.
Keystrokes for exam-specific skills
These skills are small on average but concentrated in particular exams. Learn the ones your exam uses after the core skills above.
8. Trig, inverse trig and angle mode
Where it shows up: 5.2% of PE Power and 3.6% of FE Civil questions: power-factor angles, force components, grades and surveying bearings.
Try it: reactive power for a 500 kW load at 0.85 power factor
Press mode, highlight DEG on the first line, press enter, then clear (pp. 5, 21). The trig keys are multi-tap; a second press gives the inverse (p. 24):
cos cos .85 ) enter 500 × tan 2nd [answer] ) enter
Expect θ ≈ 31.79° and Q ≈ 309.9 kvar.
Common mistake: the wrong angle mode for a typed angle. In RAD mode, 250 cos(35) returns about −225.9 instead of the 204.8 N component you expect in degrees. Glance at the DEG or RAD indicator before every trig entry. To force degrees for one entry without changing mode, add the ° modifier from math → the DMS tab (p. 21).
9. Statistics (FE only)
Where it shows up: 3.1–5.1% of each FE exam and almost none of the PE exams in our banks.
Try it: mean and standard deviation of 4.2, 3.8, 4.5, 4.0, 4.1
- Press data. If L1 holds old values, press data again and choose the clear option for L1 (pp. 34, 40).
- Type each value into L1 and press ↓ after it. Check that exactly five rows are filled.
- Press 2nd [stat-reg/distr] and select 2: 1-Var Stats (p. 36).
- Leave DATA as L1 and FRQ as ONE, move to CALC and press enter (p. 41).
Expect n = 5, mean 4.12, sample Sx ≈ 0.2588 and population σx ≈ 0.2315 (p. 40 defines both).
For a normal or binomial probability, press 2nd [stat-reg/distr], move → to the DISTR tab, pick the function, and fill its labeled input screen (p. 38). The TI-36X Pro does not use TI-84-style comma arguments here.
Common mistake: reading Sx when the question describes a whole population, or the reverse. A wrong n usually means leftover list data.
10. Numeric integral (FE only)
Where it shows up: 2.2–4.0% of FE questions, mostly in shared mathematics and in Mechanical and Environmental questions; almost none on the PE.
Try it: work done by F(x) = 3x² + 2x N from x = 0 to 2 m
Press 2nd [∫□dx] and fill the template: lower limit, →, upper limit, →, expression (p. 29):
0 → 2 → 3 x x² + 2 x → enter
Expect 12 J. Check by hand: [x³ + x²] from 0 to 2 = 8 + 4.
Common mistake: DEG mode with a trig integrand. Calculus identities for sine and cosine assume radians, so switch to RAD first.
11. Complex numbers (FE Electrical and Computer, PE Power)
Where it shows up: 2.0% of FE Electrical and Computer and 2.5% of PE Power questions: impedances, phasor currents and complex power.
Try it: current magnitude and angle for 120∠0° V across Z = 6 + j8 Ω
In DEG mode, find |Z| and its angle with the 2nd [complex] menu. Enter i by pressing the π key three times (pp. 69–70):
2nd [complex] 3 ( 6 + 8 π π π ) enter 2nd [complex] 2 6 + 8 π π π ) enter
Expect |Z| = 10 Ω and ∠Z ≈ 53.13°, so I = 120/10 = 12 A at −53.13°. To see complex results in polar form directly, choose r∠θ on the REAL / a+bi / r∠θ line of mode (pp. 6, 69).
Common mistake: RAD mode. The same angle( entry returns 0.927 in radians, the guidebook’s own RAD example for 3 + 4i (p. 70).
12. Base conversion (FE Electrical and Computer, PE Computer Engineering)
Where it shows up: 2.3% of FE Electrical and Computer and 2.7% of PE Computer Engineering questions: addresses, masks and register values.
Try it: decimal 200 in hexadecimal and binary
In DEC mode, 2nd [base n] opens the CONVR menu: 1 ▸Hex, 2 ▸Bin, 3 ▸Dec, 4 ▸Oct (p. 61).
200 2nd [base n] 1 enter 200 2nd [base n] 2 enter
Expect C8h and 11001000b. The guidebook’s own example converts 127 to 7Fh (p. 62).
Common mistake: leaving the calculator in HEX or BIN mode after a conversion. The DEC / HEX / BIN / OCT line of mode sets the base used for all calculations (p. 6), so restore DEC before ordinary arithmetic.
What about the solvers and matrices?
Learn them, but after the skills above. num-solv, poly-solv, sys-solv and the matrix editor appear in about 1% of FE questions each and almost no PE questions in our banks. When one does apply, it can save several minutes of algebra. The calculator guide’s solver and matrix walkthroughs cover them step by step.
Using a Casio fx-115ES PLUS instead?
The Casio fx-115 family is also on the NCEES approved list. The same skills matter; only the keys change. Where we are confident of the layout:
| Skill | TI-36X Pro | Casio fx-115ES PLUS |
|---|---|---|
| Scientific notation | EE | ×10x |
| ln and log | One multi-tap ln log key | Separate ln and log keys |
| Store a value | sto→, then the variable key | SHIFT RCL (STO), then a variable such as A |
| Complex, statistics, base, table | Menus on the home screen | Separate calculation modes selected with MODE |
Confirm everything else in your Casio manual. If you already know one of these calculators, do not switch for a speed advantage; we have not measured one.
How should you practice these skills?
Use the approved calculator you will take into the exam. The May 2026 Examinee Guide allows one NCEES-approved calculator in the testing room, and the approved list includes the TI-36X and Casio fx-115 families; spares stay with your stored belongings, and an on-screen TI-30XS is available during the exam. Recheck the NCEES calculator policy for your exam date.
- Budget the time. Our study planner allots about 3 hours of calculator practice for the FE and 2 for the PE, as 20-minute sessions early in the plan. It doubles that if you are new to the TI-36X Pro: about 6 hours for the FE and 4 for the PE. The study-schedule guide shows where those sessions fall.
- Follow your exam’s order. Work down your row of the practice-first table. Repeat each worked example here until you can do it without reading the steps, then change the numbers.
- Drill in the Guided Calculator Lab. In the study app, the Calculator Lab starts with a Core Calculator Skills track (EE, mode checks, stored values, parentheses) and a Gotcha Checks track, then offers a track for each FE discipline and for every PE exam we cover: Civil WRE, Structural, Transportation, Power, Computer Engineering and ECC. Each track's drills are chosen for the work that exam asks for; rehearse the same steps on your handheld, because on-screen and physical keys differ.
- Move into mixed questions. A drill tells you which function to use; an exam question does not. Try a free practice set and note whether each miss came from the method, the lookup, the keys or the units.
Get the calculator drill starter by email
A short plan for your first calculator sessions: a mode check, one function at a time, and an error log for repeated slips. Pick your exam if you want it tailored.
Frequently asked questions
Which TI-36X Pro functions matter most for the FE exam?
Clean expression entry, powers and roots, and stored values come first. In our FE practice banks, about 46% of questions are tagged for multi-step arithmetic entry and about 20% for powers or roots, while solvers and matrices each appear in about 1%. Statistics, logs and numeric integrals are worth a short drill each.
Do PE exam questions use the TI-36X Pro solvers and statistics menus?
Rarely in our PE banks: solvers, matrices, numeric calculus and statistics are each under 0.5% of PE questions on average. PE questions lean on long arithmetic chains, stored intermediates and table work, plus exam-specific skills such as complex numbers for PE Power, base conversion for Computer Engineering, and scientific notation, unit conversion and dB for ECC.
Is the TI-36X Pro allowed on the FE and PE exams?
The TI-36X family is on the NCEES approved-calculator list, as is the Casio fx-115 family. The May 2026 Examinee Guide allows one approved calculator in the testing room and provides an on-screen TI-30XS. Recheck the NCEES Calculator Policy for your exam date.
How long should I practice with the TI-36X Pro before the exam?
Our study planner budgets about 3 hours of calculator practice for the FE and 2 hours for the PE, in 20-minute sessions early in the plan. It doubles that if you are new to the TI-36X Pro: about 6 hours for the FE and 4 for the PE.
Independence note: FE Test Prep is not affiliated with NCEES or Texas Instruments. The skill shares describe our own practice questions, not official exam content. The NCEES Calculator Policy and your calculator’s guidebook control exam-day rules and device behavior.
Practice the keystrokes on real exam-style questions
Calculation questions in the study app show TI-36X Pro calculator steps, and the Guided Calculator Lab has a track for your exam. Start with a free practice set to see where your calculator work slows you down.