with integer coeficients
  - Variables only
  - Variables and numbers
  - Mixed problems
with decimal coeficients
  - Variables only
  - Variables and numbers
  - Mixed problemsg
with exponents
  - Whole numbers only
  - With decimals
multiply terms
  - Whole numbers only
complete integer coefficients
  - Variables only
  - Variables only -2-
  - Variables only -expert-
  - Variables and numbers
complete decimal coefficients
  - Variables only
  - Variables only -2-
  - Variables only -expert-
memory games
  - add&subtract
  - add&multiply -1-
  - add&multiply -2-
  - divide&multiply
  - mixed items

Adding and subtracting
  - Correctly transformed? - level 1
  - Correctly transformed? - expert
  - Add two polynomials
  - Subtract two polynomials
  - Add & Sub two polynomials
  - Tricky problem
  - Three polynomials - top level
Pyramids of expressions
  - Pyramid level 1
  - Pyramid level 2
  - Pyramid -expert-
  - Pyramid -expert 2-
  - Pyramid -top expert-
Repeat distributive law
  - Visualization
  - Find missing measure
  - Measuring a rectangle
  - Illustrative exercise
  - Convert texts to expressions
  - number times bracket
  - bracket times number
  - mixed problems
  - Multiplying out -1-
  - Multiplying out -2-
  - Multiplying out -Profi-
  - Factoring out -1-
  - Factoring out -2-
  - Factoring out -expert-
Multiplying polynomials
  - Visualization
  - Using partial product
  - Correctly transformed?
  - Practice on level -1-
  - Practice on level -2-
  - for professionals -1-
  - for professionals -2-
  - for experts only
  - Tricky problem
Geometric applications
  - Rectangles as expressions

Basics
  - Square numbers 1² to 25²
  - Square numbers 0.1² bis 2.5²
  - Memory 1² bis 25²
  - Memory 0.1² bis 2.5²
Derivations
  - Square of a Sum
  - Square of a Difference
  - Difference of two squares
Coefficient of x² is 1 - with click
  - Square of a Sum
  - Square of a Difference
  - Combined exercise
  - Difference of two squares
  - Direction left to right
  - Direction right to left
  - for professionals only
Coefficient of x² ≠ 1 - with click
  - Direction left to right
  - Direction right to left
  - for professionals only
>Coefficient of x² is 1 - free typing
  - Square of a Sum
  - Square of a Difference
  - Combined exercise
  - Difference of two squares
  - Direction left to right
  - Direction right to left
  - Direction right to left -2-
  - for professionals only
Coefficient of x² ≠ 1- free typing
  - Direction left to right
  - Direction right to left
  - for professionals only
Tricky - but nice
  - First challenge
  - Second challenge

Type 1: ax = c and x + b = c
  - Corresponding scale model
  - Corresponding line model
  - Problems on level 1
  - Problems on level 2
  - Find the equation
Type 2: ax + b = c
  - Corresponding scale model
  - Corresponding line model
  - Problems on level 1
  - Problems on level 2
Type 3: ax - b = c
  - Corresponding scale model
  - Corresponding line model
  - Problems on level 1
  - Problems on level 2
Mixed Types: x - b = c and x ÷ b = c
  - Corresponding line model
  - Problems on level 1
  - Problems on level 2
Equation sieve
  - Assign solutions
  - Assign solutions -2-
  - Assign solutions -3-
Summarizing problems
  - Corresponding line models
  - Solution trainer
  - Mixed exercise
  - Convert texts
  - Convert texts -2-

Various exercises
  - Problems on level 1
  - Problems on level 2
  - Problems on level 3

Finding & solving equations
  - Wall equation -1-
  - Wall equation -2-
  - Wall equation -3-
  - Wall equation -expert-
  - Wall equation -top expert-
  - Wall equation -champion-
Equations for advanced users
  - Task for repetition
  - ... with fractions -1-
  - ... with fractions -2-
  - ... with fractions -expert-
  - Problem level -2-
  - Problem level -3-
  - Problem level -4-
  - Problems for experts

Repeat absolute value
  - ... with visualization
Illustrative problem
  - type: |x| ± a = 0
Different types of problems
  - type: |x| ± a = 0
  - type: |x ± b| = a
  - type: |ax ± b| = c

From the drawing
  - Read intervals -1-
  - Read intervals -2-
  - Read intervals -3-
  - Read intervals -expert-
Without drawing
  - Match notations -1-
  - Match notations -1b-
  - Match notations -2-
  - Match notations -expert-

List solution elements
  - ... of the form x + b > c
  - ... of the form x - b > c
  - ... of the form b - x > c
  - ... for experts 1
  - ... for experts 2
  - ... of the form a × x > c
  - ... for top experts
Show solution sets
  - Assign solution sets
Specify solution sets
  - Type 1: x ± a > b
  - Type 2: a - x > b   difficult
  - Type 3: a ± x > b -expert-
  - Type 4: x × a > b
  - Type 5: x ÷ a > b
  - Type 4 and typ 5 champion