Formative Assessment 30

Assessment Problem: 

Let p and q be odd integers between 20 and 50. For these values, is 5p-q>2p+15 always true, sometimes true or never true?

Common Responses: 

Common Responses 3p – 15 > q
If p = 21, then 3*21 -15 = 48, so it would be true if q = 49, but not less than 49.  So, it is sometimes true.

Mathematical Issues: 

This problem encourages students to think about boundaries and ranges of numbers and how they impact inequalities.

Domain: 
Algebraic Relations
Theme: 
Inequalities
Common Core Standards: 
7.EE: Expressions and Equations
Research References: 
(Lim, 2006)