Pre-Algebra Ch. 1 Test Review
Integers Intro:
• Integers = { ..., -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, ... }
• Negative Integers = { ..., -5, -4, -3, -2, -1 }
• Positive Integers = { 1, 2, 3, 4, 5, ... }
Absolute Value:
Answers the question “How many spaces from zero?”
The number that corresponds to a point on the number line is the
coordinate of the point. The absolute value of a number is the
distance the number is from zero. Two vertical bars are used to
indicate the absolute value of a number. For example, |4| = 4 and
• |-4| = 4.
Ordering Integers:
If a number is to the left of a number on the number line, it is less than the
other number. If it is to the right then it is greater than that number.
Adding and Subtracting:
Adding like integers: just add and pass sign on to the sum
Adding unlike integers: just subtract and the number with the greater
absolute value gives its sign to the difference.
Subtracting like integers: (inverse boom) change last two signs to their
inverse (change subtraction to addition and change the sign of last number
to its opposite) – then follow rule of adding unlike integers
Subtracting unlike integers: (inverse boom) change last two signs to their
inverse and follow either directions for adding like or unlike integers
Multiplying and Dividing Integers:
Multiplying: just multiply
-when signs are the same – the answer is positive
-when signs are different – the answer is negative
Dividing: just divide
-when signs are the same – the answer is positive
-when signs are different – the answer is negative