We learned about the different groups of numbers, and the systems they work in. It was very confusing and complicated, however, as it will be useful when programming, I will try my hardest to get it right.
The first group of the numbers are called natural numbers, or whole numbers. They are numbers that are whole, like 1, 2 and 3. There are not 1.3 or 5.9.
The second group are called integers. These can be positive or negative numbers, but they must be whole.
the third group are called rational numbers, and these numbers must be able to translated into fractions.
The final group are called the real numbers, and they can be literally any number, including decimal numbers and negative numbers.
We also learned about finite and infinite sets.
Finite set = {x,y,z}
Infinite set + {x,y,z...}
Sets can also be equal to each other and yet not be the same. Here is an example:
A={2,4,6}
B={6,4,2}
It doesn't matter what order the numbers are in, as long as they are there, it counts as being an equal set.
There are also nulls sets, which are sets marked by a cicle with a diagonal line through it. It means that there is nothing in that set.
There are also subsets, which are marked by a C after the set. The opposite of this is a C with a diagonal line through it, which means that a set is not a subset. Likewise, there is a symbol that means 'included'. For example:
x,y,z ∈ A.
This literally translates to 'x,y and z are included within set A'.
In conclusion, this lesson taught us a lot, and I will brush up and test myself on this to make sure I don't forget. The number systems will be useful in coding because we might need a specific type of number to be entered to make something work.
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