# Scientific Calculator fx-991EX — Natural Textbook Calculator > Academic scientific calculator with natural textbook display and exact form results. (iPhone/iPad app by Omer Duman.) - Source: https://appshunter.io/ios/app/scientific-calculator-fx-991ex/id6760968561 (this page in markdown: same URL + `.md`) - Developer: [Omer Duman](https://appshunter.io/developer/1728850245) - Category: Education, Developer Tools - Price: Free (on sale, was $4.99) - Rating: 2.30/5 from 3 App Store ratings · 1 written reviews indexed - Age rating: 4+ - Requires: iOS 17.0 · 17 MB - Languages: American English - Released: 2026-04-03 - Data updated: 2026-08-15 - Monetization: free - User reviews in markdown: https://appshunter.io/ios/app/scientific-calculator-fx-991ex/id6760968561/reviews.md ## What is Scientific Calculator fx? Scientific Calculator fx-991EX is an academic-level scientific calculator that solves mathematical expressions in natural textbook format — fractions with horizontal bars, square roots with radical signs, and powers with superscripts, rendered exactly as they appear in your textbook. Built for university students, engineers, researchers, and professionals who need precision and clarity in every calculation. NATURAL TEXTBOOK DISPLAY Enter and view expressions in two-dimensional textbook notation. Fractions, radicals, and exponents are displayed in their true mathematical form — not as flat text. Switch between Natural Display (MathIO) and Linear Display (LineIO) anytime. EXACT FORM RESULTS Get results as simplified fractions, square roots, and π expressions — not just decimals. Toggle between exact and decimal forms instantly with S⟷D. The calculator automatically detects when a result can be expressed exactly. COMPLETE TRIGONOMETRY All standard and inverse trigonometric functions: sin, cos, tan, sin⁻¹, cos⁻¹, tan⁻¹. Three angle modes: Degrees, Radians, and Gradians. Near-zero results are snapped to exact zero to eliminate floating-point artifacts. FULL COMPLEX NUMBER SUPPORT Enter and compute with complex numbers in rectangular (a+bi) or polar (r∠θ) form. Access conjugate, magnitude, argument, real part, and imaginary part functions. Convert between rectangular and polar coordinates with Pol and Rec. FRACTIONS & MIXED NUMBERS Work with improper fractions and mixed numbers. Results are automatically reduced. Switch between mixed fraction (a b/c) and improper fraction (d/c) display with one tap. POWER & ROOT FUNCTIONS Square, cube root, nth root, arbitrary powers, reciprocal, 10^x, and e^x — all rendered in proper mathematical notation with two-dimensional templates. LOGARITHMS Base-10 logarithm (log) and natural logarithm (ln) with full precision. 40 SCIENTIFIC CONSTANTS Instantly access 40 fundamental physical constants organized in 5 groups: particle masses, quantum mechanics, electromagnetic, thermodynamic, and universal constants. Constants are displayed with their standard symbols. ADVANCED MATH FUNCTIONS • Factorial (x!) for integers 0–69 • Permutation (nPr) and Combination (nCr) • Absolute value, integer part, fractional part, floor • Random number (Ran#) and random integer (RanInt#) • Percentage calculations MEMORY & VARIABLES Store and recall values in 26 named variables (A–Z) plus an independent memory register (M) with M+ and M− operations. The last result is always available via Ans. CALCULATION HISTORY Browse up to 30 previous calculations. Scroll through history with arrow keys and replay any past expression for quick editing and recalculation. DISPLAY FORMATS • Norm — Standard notation with automatic scientific switching • Fix — Fixed decimal places (0–9 digits) • Sci — Scientific notation with configurable significant digits • 15-digit internal precision, 10+2 digit display PROFESSIONAL PRECISION 15-digit internal calculation precision. Numeric range from ±1×10⁻⁹⁹ to ±9.999999999×10⁹⁹. Automatic parenthesis closing. Multi-statement evaluation with colon separator. Full error handling with edit-mode recovery. DESIGNED FOR EDUCATION & ENGINEERING Whether you are solving homework problems, preparing for exams, or performing professional engineering calculations — Scientific Calculator Emulator gives you the accuracy and clarity of a dedicated hardware calculator on your iPhone. Some advanced features require a subscription. Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ ## Key features - Natural textbook display - Exact form results (fractions, roots, pi) - Full complex number support - Complete trigonometry functions - 40 scientific constants - Calculation history ## Recent user reviews (1 of 1) All indexed reviews: https://appshunter.io/ios/app/scientific-calculator-fx-991ex/id6760968561/reviews.md ### 1/5 — do not update to 2.0.9 *2026-08-03* 不如老版本好用！ ## Frequently asked questions about Scientific Calculator fx ### Does Scientific Calculator fx-991EX have ads? No, Scientific Calculator fx-991EX does not contain advertisements. It is a completely ad-free experience for users. ### What is the rating for Scientific Calculator fx-991EX? Scientific Calculator fx-991EX has a rating of 3.0 stars based on 2 user ratings. This indicates a mixed reception from its current user base. ### Is Scientific Calculator fx-991EX suitable for younger users? Scientific Calculator fx-991EX has an age rating of 4+, making it suitable for a wide range of users. Its advanced features are primarily geared towards academic and professional use. ### What devices does Scientific Calculator fx-991EX support? Scientific Calculator fx-991EX is supported on both iPhone and iPad devices, offering a consistent experience across Apple's mobile platforms. ### How often is Scientific Calculator fx-991EX updated? The latest version, 2.0.8, was released on April 28, 2026, indicating recent development activity. Users can expect ongoing support and potential improvements. ### Can I switch between exact and decimal results in Scientific Calculator fx-991EX? Yes, Scientific Calculator fx-991EX allows you to toggle between exact forms (like simplified fractions, square roots, and pi expressions) and decimal forms instantly using the S⟷D function. ### Does Scientific Calculator fx-991EX support complex numbers? Yes, Scientific Calculator fx-991EX offers full support for complex numbers. You can enter and compute with them in both rectangular (a+bi) and polar (r∠θ) forms. ### How many previous calculations can I access in Scientific Calculator fx-991EX? Scientific Calculator fx-991EX stores up to 30 previous calculations in its history. You can scroll through this history to edit and recalculate past expressions. ## Version history (last 5 releases) ### 2.0.9 — 2026-08-03 Minor bugs fixed! ### 2.0.8 — 2026-04-28 • Smarter delete: cursor moves naturally through fractions, powers, and mixed numbers • Stacked x²/x^ presses share one superscript line (no more diagonal staircase) • Chained-exponent results corrected (5²² → 625) ### 2.0.7 — 2026-04-27 Multi-step calculations can now run one step at a time. • Type ◢ with SHIFT+x² • Enter 1+2◢3+4 and press EXE — see the first result, press EXE again to continue • Silent (:) and pausing (◢) separators mix freely (1+2:3+4◢5+6) • From the final result, ◀/▶ restores the full expression for editing Display improvements: • Brackets render symmetrically across all expression sizes • Exponent (²) positioning fixed — sits at the bracket's upper curve Stability: • Fixed a rare crash when rapidly tapping a key • Added display-aware nesting caps for nested mathematical expressions ### 2.0.5 — 2026-04-23 Improvements in this release: • Typing after a displayed result now consistently clears the old input — including fraction, √, and π results. • x², x⁻¹, and % after a result now produce Ans², Ans⁻¹, and Ans%. On an empty screen, x² and x⁻¹ insert an empty-base template ready to be filled in. • Stronger fraction display: large-denominator results (e.g. 1/20000000) now show as fractions instead of scientific notation, and small values recover the correct fraction instead of a near-match. ### 2.0.4 — 2026-04-23 • Polar and rectangular format converters now render inline in the expression — type to their left to add content • Short decimals like 0.00011 and 0.000005 now recover their exact fraction form (11/100000, 1/200000) • Cursor realigned on the pixel grid (no more overlap on empty input or beside the convert-to arrow) ## More apps by Omer Duman - [AppsMax](https://appshunter.io/ios/app/appsmax/id6477292943) - [WhatsAI: Relationship Analysis](https://appshunter.io/ios/app/whatsai-relationship-analysis/id6744169392) - [SPF AI: Sunglow & Tanning](https://appshunter.io/ios/app/spf-ai-sunglow-and-tanning/id6747141398) - [QuitJunk AI: Food Scanner](https://appshunter.io/ios/app/quitjunk-ai-food-scanner/id6747582284) - [Glow: Color Analysis](https://appshunter.io/ios/app/glow-color-analysis/id6747744493) - [Debloat AI: Debloat Your Body](https://appshunter.io/ios/app/debloat-ai-debloat-your-body/id6748082449) All apps by Omer Duman: https://appshunter.io/developer/1728850245 ## Related topics [calculadora cientifica 991 82](https://appshunter.io/ios/topics/calculadora-cientifica-991-82) · [ncalc fx](https://appshunter.io/ios/topics/ncalc-fx) --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-15.*