Algebra I: Signed Numbers & Absolute Value

What you’ll learn

• Before every problem, name the operation: add or subtract means movement on the number line (same signs add and keep, different signs subtract and take the larger sign); multiply or divide means count the negatives (even positive, odd negative).
• Decide which rule set applies (add/subtract vs multiply/divide) before you touch the numbers.
• Same signs add and keep the sign; different signs subtract and take the sign of the larger value.
• Subtracting a negative is adding a positive.
• An even count of negative factors gives a positive product or quotient; an odd count gives a negative one.
• Absolute value is distance from zero, so it is never negative, and a sign outside the bars survives.