Headline Story
Attributes of Two-Dimensional Figures, #8
Click to enlarge
Introduction
Write the following story on the board and ask students to be prepared to justify all their responses.
Headline Story
A > B and C > D. Compare the following:
A + C __ B + D
A + D __ B + C
A – D __ B – C
What else could you say?
Possible student responses
- A + C must be greater than B + D, because the sum of two larger numbers is greater than the sum of two smaller numbers.
- A + D can be equal to, greater than, or less than B + C, because it depends on what numbers you use for A, B, C, and D.
- A – D is greater than B – C, because A – D is subtracting a smaller number from a larger number, and B – C is subtracting a larger number from a smaller one.
- Both A – D and B – C could be less than 0.
- You can’t tell whether A – C or B – D is larger.
This work is licensed under a
Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.