Lesson Plan # 10 - Introduction to Negative
numbers and the number line
- (5 min) Mental Math
- Start with 18, subtract 13, then multiply by 3 [15]
- Multiply 50 by 30 [1500]
- Multiply one-half times one-half times one-half [1/8]
- What is the area of a triangle whose base is 1/2 inch and whose
height is 1/2 inch? [1/8 sq. in.]
- What is .5 times .5? [.25]
- (15 min) Give students the Progress Quiz (no review today)
Progress Quiz Scoring Rubric:
- 9-10 points: Student who has grasped the concepts in lessons 1-9.
- 7-8 points: Average student. Should work on concepts in problems
missed.
- 5-6 points: Student who has missed some major concepts. Needs help in
areas not understood. What you do here depends on whether the student's
work exhibits sloppy computation or misunderstood concepts.
- Below 5: a 'lost' student. Probably has not been turning in homework.
Retention in this program (or steps to get homework turned in) should be a
discussion topic with student and parents.
Remember, this is the student
that you can damage mathematically by dragging them through more complex
topics in the months to come.
- (10 min) Introduce negative numbers:
- Draw this number line on the board:
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
-7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9
- Pass out the Negative number handout and follow the discussion and
examples in the handout.
- Get students to come to the board to solve these problems:
- -2 + 8 (when results are positive, get students to put "+" signs on
them)
- +5 - 10
- +2 - 5
- -4 - 3
Use the terminology "Start at [first number] and move [left/right] [second
number] places".
(Remainder of class) In-class Exercise.
Hand out homework as students successfully complete the in-class
exercise.
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