This week in PreCalc 11 we started re-learning how to classify Real Numbers. I remember learning about in on grade 10 math but I didn’t remember anything so this was the perfect refresher and I know I won’t forget again.
I chose this topic because I remember being lost and confused last year when learning about the real number system. I also felt like I was behind in class because I didn’t remember what my peers could remember. by writing out all the rules I am helping future Avery remember all this important information, along with give her something to look back on when she’s confused.
This week I learnt:
Decimal numbers which repeat or terminate can be converted into fractions and are called rational numbers since they can be written as the ratio of two integers
Decimal numbers which are both non-repeating, and non-terminating cannot be converted into fractions and are called irrational numbers
This set of all rational numbers, and the set of all irrational numbers when combined form the set of real numbers these numbers can be represented on a number line
Rational Numbers
Q
- decimal
- either terminates or repeats
- Fraction (ratio of integer)
- No zero for the denominator
Irrational numbers
the character for this is a Q with a line over it.
- cannot be a fraction
- must be a decimal
- never ends
- non repeating and non terminal decimals
exp.
5.6318…
( if there is no … or relating sign it is not irrational)
Integer
I or Z
- has No decimal
- includes positive numbers , negative numbers, whole numbers , and Zero
Whole number
W
0, 1, 2, 3, 4, 5, …
Natural
N
1, 2, 3, 4, 5, 5, …
- is considered to be counting numbers (what your parents teach you)
- No Zero
Real numbers
R
Real numbers are both rational and irrational numbers

this is a digital version of the chart we drew in class.
another good mention is: square roots
specifically to help myself is to remember all positive numbers have two square roots, a positive number, and the other a negative number the positive square root is called the principal square root, and is denoted by the symbol√ .
- The square root of a perfect square are rational numbers
eg. the square roots of 16 aret be 4 and -4
Note: √16 = 4 only
- The square roots of a non-perfect square are irrational
eg. the square roots of 17 are √17 and √-17
1²=1
2²=4
3²=9
4²=16
5²=25
6²=36
7²=49
8²=64
9²=81
10²=100
11²=120
12²=144
13²=169
14²=196
15²=225
that’s all…
hope that helps 🙂