Online scientific calculator: a guide with worked examples

The Zero7Files calculator works like a natural-display scientific calculator: you type fractions, roots and integrals as they look in a textbook and get exact results such as ½, √2 or π/3. This guide walks through the most useful features with examples you can reproduce.

Open the calculator

The calculator's on-screen menus are in Spanish. Below, each menu name is given as it appears on screen, followed by its meaning — for example Ecuación/Func (Equation/Function).

The basics: SHIFT, ALPHA, MENU and OPTN

Every key has a main function and two secondary ones. The yellow one (top left above the key) is used by pressing SHIFT first; the red one, with ALPHA.
MENU shows the 12 calculation modes: Calculate, Complex, Base-N, Matrix, Vector, Statistics, Distribution, Spreadsheet, Table, Equation/Function, Inequality and Verify. Pick one by its number, or with the (−), °′″ and x⁻¹ keys for A, B and C.
OPTN opens the functions of the current mode: hyperbolic functions, angle units, statistics, matrices…
SHIFT MENU opens the setup: degrees or radians, number of decimals (FIX), scientific notation, decimal point or comma…
The arrows move the cursor. When you're not typing, ▲ brings back previous calculations.

Fractions, roots and powers in 2D

Press ▫/▫ to create an empty fraction. Type the numerator, move down to the denominator with ▼ and leave the fraction with ▶. The same applies to √▫, the power x^▫ or the logarithm in any base (ALPHA log).

Example: 1/3 + 1/6 gives 1/2. The S⇔D key toggles between the exact result and the decimal (0.5). For the decimal straight away, press SHIFT =.

Exact results include roots and π: √8 + 1 gives 1 + 2√2 and sin(45) in degrees gives √2/2. (The sine key is labelled sen, its Spanish name.)

Integrals and derivatives

Press ∫▫. The integral template appears with three boxes: the function, the lower limit and the upper limit. Type the function using the x key, move to the lower limit with ▶, enter it, move to the upper limit, enter it and press =.

Calculation	Result
∫ from 0 to 1 of x² dx	1/3
∫ from 1 to e of ln(x) dx	1
∫ from 0 to √3 of 1/(x²+1) dx	π/3

The derivative at a point is on SHIFT ∫▫ (d/dx): type the function and the point in the x= box. For example, the derivative of x³ at x = 2 is 12. Sums Σ (SHIFT x) and products Π (ALPHA x) work the same way: Σ of x from 1 to 100 gives 5050.

If the function contains sines or cosines, switch to radians first in SHIFT MENU → Unidad angular (angle unit). In degrees, ∫ sin(x) from 0 to 180 isn't 2 but 360/π, because each degree is π/180 radians.

Solving equations

Quadratic, cubic and quartic equations

MENU → Ecuación/Func (the (−) key) → Polinómica (polynomial) → pick the degree.
Enter the coefficients, pressing = after each one. For x² + 2x − 2 = 0: 1, 2, −2.
Press = again to solve. You'll see x₁ = −1 + √3 and, pressing = again, x₂ = −1 − √3. For quadratics the parabola's minimum or maximum is shown too.

Complex solutions are shown as well, such as ±i for x² + 1 = 0. You can turn them off in the setup (Ecuación/Func → Complejos Off).

Systems with 2, 3 or 4 unknowns

In the same mode, choose Sist ec lineal (linear system). For x + 2y = 3 and 2x + 3y = 4, enter the rows 1, 2, 3 and 2, 3, 4. The solution is x = −1, y = 2. If the system has no solution or infinitely many, the calculator says so.

Any equation: SOLVE

In Calculate mode, type the equation with the equals sign (ALPHA CALC), for example x² = 2, and press SHIFT CALC (SOLVE). Enter a starting value and press =: you'll get x = 1.414213562 and the check L−R = 0.

Statistics and regressions

MENU → Estadística (statistics) and choose the type: one variable or one of the seven regressions (linear, quadratic, logarithmic, exponential, power and inverse).
Type the data into the table, pressing = after each value. Move between cells with ▲▼◀▶.
Press OPTN → Cálc regresión to see a, b and the correlation coefficient r, or Cálc 1-variable for the mean, standard deviation, quartiles and so on.

To predict a value, press AC to go to the calculation screen and use OPTN → Regresión → ŷ. For example, 160ŷ gives the predicted y for x = 160.

Other useful modes

Complex: the ENG key types i. (1 + i)⁴ + (1 − i)² = −4 − 2i. OPTN gives the conjugate, modulus, argument and polar form.
Matrix and Vector: define MatA…MatD or VctA…VctD from OPTN and calculate with them: determinant, inverse, transpose, dot or cross product and angle between vectors.
Distribution: normal (density, cumulative and inverse), binomial and Poisson.
Table: builds a table of values for f(x) and g(x) between a start and an end with the step you choose.
Inequality: solves polynomials of degree 2 to 4 with >, <, ≥ or ≤, e.g. x² + 2x − 3 < 0 → −3 < x < 1.
Base-N: binary, octal, decimal and hexadecimal, with and, or, xor and not.

Typing with your computer keyboard

You don't have to click the on-screen keys. You can type function names: cos(60), sqrt(8), int(x^2,0,1), der(x^3,2), pi, ans… They turn into the function when you type (. Inside a template, a comma moves to the next box and ) leaves it. Also:

Enter calculates; = types the equals sign.
- is a negative sign at the start or after an operator, so 5--3 gives 8.
The key to the left of 1 (` on US keyboards, º on Spanish ones) acts as SHIFT, and Tab as ALPHA.

Most common errors

ERROR Sintaxis (syntax error): an empty box, a missing bracket or argument. Press ◀ or ▶ to go back to the calculation with the cursor near the error.
ERROR Cálculo (math error): the operation isn't possible, such as dividing by zero or the logarithm of a negative number.
ERROR Dimensión (dimension error): the matrices or vectors don't have compatible sizes.

The calculator remembers your variables, Ans and setup even if you close the tab. To start from scratch, go to SHIFT 9 (RESET) → Iniciar todo (initialize all).