Mean, Median, Mode

[Butter]

I am in seventh grade I am learning about the applications of mean, median and mode.
In a book it clearly states that, " The mean, median and mode are measures if central tendency."
What does this mean?

 

[MarkFL]

From Wikipedia:

In statistics, the term central tendency relates to the way in which quantitative data tend to cluster around some value. A measure of central tendency is any of a number of ways of specifying this "central value". In practical statistical analysis, the terms are often used before one has chosen even a preliminary form of analysis: thus an initial objective might be to "choose an appropriate measure of central tendency".