Maryland Math 7.AT.C.9

7.AT.C.9 is a cluster heading. These are the individual standards under it.

• 7.AT.C.9.a

  Write inequalities of the form px + q > r or px + q < r, where p, q, and r are specific rational numbers.

• 7.AT.C.9.b

  Solve inequalities of these forms and graph the solution set on a number line.

• 7.AT.C.9.c

  Interpret the solution set in terms of the context by describing what values are possible or reasonable in the given situation.

01

What Students Need to Do

Students choose a variable, write an inequality for a limit, and solve it using rational numbers. They graph the solution on a number line and decide which values make sense in the situation.

02

What Mastery Looks Like

Given a $20 gift card and snacks costing $2.50 each, a student writes 20 − 2.5x > 5 to show that more than $5 remains. They solve x < 6, draw an open circle at 6, and name 0 through 5 as the possible snack counts.

03

Common Misconceptions

Students may write > when a total must stay below a limit. They may forget to reverse the sign when dividing by a negative number. Some include an open endpoint or give fractional counts for items that must be whole.

04

How to Assess It

Give this exit ticket: A $4 fee plus $2.50 per ticket must cost less than $19. Write and solve an inequality, graph it, and list the possible whole-number ticket counts.

1. 01

   Give pairs play money, a $4 entry-fee card, and $2.50 ticket cards; have them build purchases under $19 and mark possible counts.

2. 02

   Have students write why six tickets fail a strictly under $19 limit and why the graph has an open circle at 6.

3. 03

   Run a card sort matching −0.5x + 3 > 1 and 2x + 1 < 7 to solutions and number-line graphs.

4. 04

   Have students check how many 1.5 GB movies fit on a phone plan with 2 GB already used and a 12 GB cap.

• 6.AT.C.10

  Solve problems in context by writing and solving inequalities and interpreting solution sets in context.

• 7.AT.C.8

  Use variables to represent quantities and write and solve equations to model and reason about relationships in context.

• 6.AT.C.10.a

  Explain that a variable can represent an unknown number in a set and use substitution to determine whether a given number in a set makes an inequality true.

• 6.AT.D.11

  Use variables to represent two quantities in context that change in relationship to one another.