se’. Unfortunately, the system does not recognize typ-
ical student mistakes. If a student does not under-
stand a particular problem, he/she can always access
a complete explanation. The explanation offers also
some additional theory if necessary. However, even if
ALEKS recognizes that a part of solution is correct,
it presents the same explanation as for user who does
not know how to start to solve the problem. When
the student gives sufficient amount of correct answers
to a given topic, ALEKS considers that the student
has learned the topic and the student chooses another
topic to learn.
Another example is ActiveMath (DFKI, Saarland
University) (Melis, 2011) — the intelligent and in-
teractive project. It is a web-based, multi-lingual,
learner-centered system for mathematics which con-
tains different topics realized at schools, universities
and it is also a good tool for life-long learning. It helps
the student in self-regulated learning, can adapt to in-
dividual knowledge and personal interests and learn-
ing goals. The system also presents information on
student improvement. The user of this platform has
to fill in the input field with the final result of his/her
calculations. In the case of a correct answer, the sys-
tem informs the student that the answer is correct and
shows the complete solution. Otherwise it suggests to
try again or to ask for some hints. By clicking several
times on the ‘hint’ button, one may obtain the com-
plete solution.
In Poland, the platform (Wa˙zniak, 2006) is very
popular. It was built by a few leading Polish univer-
sities and it offers e-learning courses for mathematics
(among other) at the level of secondary and tertiary
education. The systems offers attractive theory (e.g.
with animations), practical tasks, and tests. There are
hints on request or, in case of more complex exercises,
the plans of solution. It is also possible to see the com-
plete solution. The student can solve the exercise on
his/her own, eventually using the hint and then com-
paring his/her solution with the one presented by the
system.
The Infinite Series Tutorial (the part of (Bogacki,
2009) developed by Przemyslaw Bogacki from Old
Dominion University), presents a little different ap-
proach and for this reason it is remarkable. The stu-
dent has to choose the answer (i.e. converges abso-
lutely, converges conditionally, or diverges) and then
give the reason of his answer (the proper convergence
test). Then the system discusses the student’s answer,
eventually suggests the other possible solution paths.
So in the case of an incorrect answer, it is possible to
try again or to give up and see the complete solution.
The tutorial also collects information on numbers of
solved tasks.
Our platform differs from other already exploited
ones. In the described systems (Wa˙zniak, 2006;
ALEKS, 2011; Bogacki, 2009; Melis, 2011) the stu-
dent does not know what kind of error he/she has
done, only comparing his/her solution with the one
given by the system, he/she can find the mistake (only
in the case he/she has chosen the same solution path
as is given by the system ), but it is too late to con-
tinue the solution on his/her own. Let us stress the
main differences in the approach to solving exercises
that appear in our and described platforms. In our
system the two main paths are offered. The first one
is the path of checking the answer, and the second is
the path of hints. The student that needs more help
can choose this path of hints and then is lead step by
step through the solution of a problem. He/she has to
make some calculations on his/her own and then fill
in the input fields. The system verifies the correctness
of each step, recognizes typical mistakes and then in-
forms the student about his mistakes, gives more hints
or explanations. It allows the student to correct imme-
diately his/her error and continue the calculations. In
many points of this path of solution there is a possi-
bility to abandon this main path, finish the exercise on
one’s own and check the answer. In the case of check-
ing the answer, the system examines the correctness
of the solution (if possible) by giving some additional
questions.
4 IMPLEMENTATION
To implement our system we use LaTeX, PHP, C and
JavaScript languages.
4.1 Main Ideas
The main idea of the system is as following: a student
logins into the system and can choose a problem to
learn. After some sessions, the system would be able
to propose some problems according to the difficulties
and errors made by the student. To make it possible
the system registers the student’s activity. One distin-
guished action is to solve one problem.
A solution of a problem is divided into pages.
Each page is presented to the student with contents
and some possible actions to be taken. He/she can
make a decision: choose some expression from a list
or write some number/text to an input field. After-
wards, the student can chooses an action to be taken
by clicking on a button, although occasionally there
will only be one button present. Each button is related
to one or more pages. If there are more pages then
the choice depends on the previous decisions made
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