Introduction to the mathematical concept of FUNCTION (8th grade math)

In mathematics, a function is a relation between two sets where each element in the first set is mapped to exactly one element in the second set. The first set is the set of INPUTS and the second set is the set of OUTPUTS. So, each input is mapped to exactly one output.

But what if some of the outputs are the same? Is that allowed? What if some element has no output? For example, in the example about rooms and their colors, what if some room has no color assigned to it? Is it a function?

We also look at some numerical examples where a function is given as a list of ordered pairs. A function can also be given as a rule, such as x mapping to x squared. We look at the graph of that function in the coordinate plane (for certain integer values only).

See also

Linear functions and the rate of change, part 1 — video lesson

Math Mammoth Grade 8 curriculum

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