Seventh Grade · Math · week 17

Error analysis: signed numbers

Find and correct sign errors and order-of-operations mistakes in worked solutions involving signed numbers.

Finding someone else's mistake is a powerful way to test your own understanding -- you have to know the rule well enough to spot exactly where it was broken, not just get lucky with a final answer.

This week, look at worked solutions that already have an answer written down, decide if it is right, and if not, name the exact step where the error happened and fix it.

📋 For the teacher
Teach it (10–15 min):
  • Resist the urge to just tell them the right answer -- ask "where exactly does this stop being correct?" first.
  • Have them name the RULE that was broken (order of operations, or the sign rule), not just say "it is wrong."
  • Praise catching the error itself as the real skill this week, separate from being able to solve the original problem.
  • Ask them to write their own flawed solution for you to find the error in -- it flips the challenge around.
Talk about it:
  • Why is finding someone else's mistake sometimes harder than solving the problem yourself?
  • What are the two most common signed-number mistakes you have seen this unit?
  • How would you explain the fix to a friend who made one of these errors?

Mastery looks like: They correctly identify the specific error in a flawed solution, name the rule that was broken, and produce the correct answer.

Common stumbles: Redoing the whole problem from scratch instead of pinpointing the exact flawed step; fixing the arithmetic but not naming the rule that was broken.

Homework for this lessonType it, write it with a stylus, or print it for pencil & paper.open →
Records attendance + 15 min of Math for this learner.
← Back to todayAll coursesYear planner