## Overview

### Aplusix concept

An Aplusix resource proposes exercises.

At launch, the application opens with an exercise statement and the starting expression of the firs exercise.

The user can do her own step from a new empty step or by changing a copy of the starting expression, with the virtual keyboard of Aplusix.

For each action, Aplusix checks the syntax of the expression and the equivalence with the previous step.

Aplusix indicates when the exercise is solved. It also indicates "almost solved" when there are only few simplifications left.

### The type of the exercise

Aplusix deals with the following types of exercises:

- Numerical calculations
- Expand and simplify a polynomial (one or several variables, any degree)
- Factoring a polynomial (one variable, any degree)
- Solving an equation (degree 1 to 4)
- Solving an inequality (degree 1 to 4)
- Solving a system of equations

### General settings

When an aplusix web page starts, a general settings panel is visible on the top of the application.

As soon as you click or touch inside to enter something, this panel will be replaced by a virtual keyboard at the bottom of the application.
It will appear again if you close the virtual keyboard.

Function of the buttons (from the left to the right):

- New blank exercise
- French or English version
- Decrease or increase width
- Decrease or increase height
- Decrease or increase police size

### Buttons

#### Ending the exercise, next exercise, previous exercise

Function of the buttons (from the left to the right):

- End of the exercise(button also used to tell if the equation has no solution or if every number is a solution)
- Back to the previous exercise
- Next exercise

#### Steps

Function of the buttons (from the left to the right):

- Delete the step
- Create a new empty step
- Create a new step with a copy of the previous step

#### Editing

Function of the buttons (from the left to the right):

- Undo, Redo
- Move the cursor according to the direction of the arrow
- Delete

### Feedback

For each action, Aplusix Web indicates syntax problems and, when the expression is well formed, the equivalence of the step with the previous one.

- Equivalent step: green check mark.
- Non equivalent step: red cross.
- Incomplete expression, out of domain or with a different status: blue cross.
- Not comparable expression ( for example a polynomial and an equation) : black cross.
- Aplusix Web displays a green check mark followed by "Solved" if the step ends the exercises.
- Aplusix Web displays a green check mark followed by "Almost solved" if there remain only some simple calculations to solve the exercise.