1.5 Change in a Quantity and Subtracting Real Numbers
Change in a Quantity
Change in the quantity = Ending amount Beginning Amount
Subtracting a Real Number
To subtract a number, add its opposite
a b = a + (-b)
Changes of Increasing and Decreasing Quantit

1.2 Expressions
Expression: A constant, a variable, or a combination of constants, variables,
operation symbols, and grouping symbols, such as parentheses.
Evaluating an Expression: Substituting a number for each variable in the
expression and then calcul

1.4 Absolute Value and Adding Real Numbers
The Opposite of a Number
Two numbers are called opposites of each other if they are the same
distance from 0 on the number line.
Finding The Opposite of a Number
The opposite of the opposite of a number is equal

1.3 Operations with Fractions and Proportions; Converting Units
Meaning of a Fraction
A fraction can be used to describe a part of a whole.
a
-b
8
- = 8 4 = 2
4
Division by Zero
The fraction a/b is undefined if b=0. Division by zero is undefined.
Ex. 3/0

1.1 Variables, Constants, Plotting Points, and Inequalities
Variables
In arithmetic, we deal with numbers. In algebra and statistics, we work with
variables as well as numbers.
Variable: a symbol that represents a quantity that can vary.
ex. The number of