How to use this sheet

  • Keep a number line from −20 to 20 beside the sheet for every problem the child is unsure of.
  • Have the child say the problem as a story, such as the temperature or money owed.
  • For multiplying and dividing, have the child decide the sign first, then work out the number.

Common mistakes

  • Thinking −8 is greater than −3 because 8 is greater than 3. On the number line, −8 is further left, so it is less.
  • Using the multiplying sign rule for adding, so −3 + −5 becomes 8. Two negatives added make a bigger negative: −8.
  • Dropping the sign when subtracting a negative, so 4 − (−2) becomes 2. Subtracting a negative is adding: 6.

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