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)