ROATEE 991ES Office Calculators Desktop
Rating
Product Overview
The ROATEE 991ES is a scientific calculator designed for students and professionals. It features 417 functions, a 4-line display, and an integrated LCD writing tablet with a stylus. It supports general math, science, algebra, geometry, statistics, calculus, and more. The calculator is dual-powered by solar and a coin battery. Its anti-drop body and lightweight design make it portable and durable. It is suitable for school, business, and everyday calculations.
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Product Specifications
Size & Weight
Features
This function allows you to solve for unknown variables in equations directly on the calculator. Instead of manually manipulating equations, you can input the equation and find the solution, saving time and reducing errors, especially useful for complex algebraic problems.
The calculator includes an equation solver function, allowing users to solve for unknown variables in equations. This function can be useful for algebra and calculus problems. However, the functionality may be limited compared to dedicated equation-solving software.
This function enables you to perform operations on matrices, such as addition, subtraction, multiplication, and finding determinants and inverses. Useful for linear algebra calculations in subjects like engineering, physics, and computer graphics.
The calculator supports matrix calculations, including addition, subtraction, and multiplication. This function is useful for linear algebra and engineering applications. However, the matrix size and complexity may be limited compared to more advanced calculators.
This function allows calculations involving complex numbers, including addition, subtraction, multiplication, division, and finding magnitudes and arguments. Simplifies calculations in electrical engineering, quantum mechanics, and other fields involving imaginary numbers.
The calculator does not support complex number calculations. This is a significant limitation for users in electrical engineering, physics, and other fields that require complex number operations. Users needing this function should consider alternative calculators.
This function allows you to perform calculations in different number systems, such as binary, octal, and hexadecimal, in addition to decimal. Useful for computer science and digital electronics, where these number systems are frequently used.
The calculator supports base-N calculations, including binary, octal, and hexadecimal. This function is useful for computer science and digital electronics applications. However, the functionality may be limited compared to dedicated base-N converters.
This function enables you to perform statistical analysis, including calculating mean, standard deviation, variance, and distributions. Useful for statistics courses, data analysis, and research projects.
The calculator includes statistical calculation functions, such as mean, standard deviation, and regression analysis. These functions are useful for statistics courses and data analysis projects. However, the range of statistical functions may be limited compared to dedicated statistical software.
This function allows you to easily convert between different units of measurement, such as length, mass, volume, and temperature. Saves time and reduces errors when working with different units in physics, chemistry, or engineering problems.
The calculator does not have a dedicated unit conversion function. This is a limitation for users who frequently need to convert between different units of measurement. However, users can manually perform unit conversions using the calculator's basic arithmetic functions.
SHOPSTAFF Rating Score
The ROATEE 991ES is a budget-friendly scientific calculator with a unique writing tablet feature. It offers a wide range of functions suitable for students and basic scientific use. However, it lacks some advanced features found in higher-end models and the brand reliability is questionable.
Brand & Manufacturer Details
Key Highlights
- Integrated LCD writing tablet
- Dual power source
- Lightweight and portable
- Affordable price
Considerations
- Writing tablet functionality depends on lock key
- Durability may be a concern due to brand
- Limited advanced functions
Recommended For
- High school students
- College students
- General science users
- Budget-conscious buyers
Not Recommended For
- Advanced engineers
- Researchers needing high precision
- Users requiring graphing capabilities
Suitable For
- Classroom
- Homework
- Basic office calculations
- On-the-go calculations
Not Suitable For
- Advanced engineering simulations
- High-level statistical analysis
- Complex financial modeling
Frequently Asked Questions (FAQ)
Q.Is this calculator suitable for high school and college students?
Q.Does the calculator have a feature to prevent accidental erasing of notes on the writing pad?
Q.How durable is this calculator?
Q.Is the calculator easy to use?
Q.Does the writing pad have a way to save notes?
SHOPSTAFF Rating Ranking
Casio FX-991ES Plus-2nd Edition Scientific Calculator with Natural Textbook Display and 417 functions.
| Display Digits | 10 + 2 digits | Display Type | LCD (dot-matrix) |
| Power Source | Solar & Battery | Number of Functions | 417 |
| Memory | - locations | Fractions | Yes |
| Complex Numbers | Yes | Statistics Functions | Yes |
| Regression Analysis | - | Unit Conversions | - |
Casio fx-991CW Advanced Scientific Calculator with High-Res 4-Tone Display and 540+ Functions.
| Display Digits | - digits | Display Type | High-Resolution 4-Tone |
| Power Source | Solar Powered | Number of Functions | 540+ |
| Memory | 9 locations | Fractions | Yes |
| Complex Numbers | - | Statistics Functions | Yes |
| Regression Analysis | - | Unit Conversions | Yes |
Casio
fx-115ES Plus 2nd Edition Advanced Scientific Calculator
$16.99(incl. tax)Amazon price as of 2025-09-29
Casio fx-115ES Plus 2nd Edition: Advanced scientific calculator with Natural Textbook Display and 280+ functions.
| Display Digits | 16 digits | Display Type | LCD |
| Power Source | Solar Powered | Number of Functions | 280 |
| Memory | 9 locations | Fractions | Yes |
| Complex Numbers | Yes | Statistics Functions | Yes |
| Regression Analysis | Yes | Unit Conversions | Yes |
Texas Instruments
TI-36X Pro Engineering/Scientific Calculator
$20(incl. tax)Amazon price as of 2025-09-24
TI-36X Pro: Engineering/Scientific calculator with MultiView display, ideal for high school through college.
| Display Digits | - digits | Display Type | LCD |
| Power Source | Battery Powered | Number of Functions | - |
| Memory | - locations | Fractions | Yes |
| Complex Numbers | No | Statistics Functions | Yes |
| Regression Analysis | Yes | Unit Conversions | Yes |
TI-30XIIS: A fundamental two-line scientific calculator for high school math and science with solar and battery power.
| Display Digits | 12 digits | Display Type | LCD |
| Power Source | Solar & Battery | Number of Functions | - |
| Memory | 5 locations | Fractions | Yes |
| Complex Numbers | No | Statistics Functions | Yes |
| Regression Analysis | Yes | Unit Conversions | Yes |
