Day 2 – August 27

Algebra: Chapter 1, Lesson 1, page 4.

Symbols and Expressions

In algebra, we use symbols to stand for various numbers. One type of symbol is called a VARIABLE. An expression such as `396/v` and contains at least one variable is called an ALGEBRAIC EXPRESSION. We can replace a variable with a number, this is called SUBSTITUTING for the variable.

Sets of numbers:

  • Natural: 1, 2, 3, 4, 5, …
  • Whole: 0, 1, 2, 3, 4, 5, …
  • Rational: numbers which include natural and whole numbers and can be expressed as a RATIO such as `1/1` or `2/3`

Parenthesis (, ) or [,] or {,} are called GROUPING SYMBOLS and we do things in them first.

PEMDAS, please excuse my dear aunt sally – order of operations. Just like in Language Arts, we have a convention of writing/reading from left to right, we have a convention in math.
We do things in the order of:

  1. parenthesis
  2. exponents
  3. multiplication/division (in order from left to right)
  4. addition/subtractions (also in order from left to right).
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