GB-02-05-001 · Reasoning with signed calculations
A student writes . Explain the mistake and give the correct answer.
Directed Numbers: Identifying Sign Errors
Application of related method — Booklet p. 27
Method
1) Touching signs: + (−b) means subtract b, moving further left on the number line
2) Do not confuse addition of negatives with multiplying two negatives
Worked Example (GB-02-05-001)
1)
Adding a negative decreases the value; the rule for multiplying two negatives does not apply.
2)
Ans =