A comprehensive Regents-aligned Algebra 1 sequence guiding students from reading and graphing inequalities on number lines to mastering multi-step linear inequalities using the visual Boxes and Circles cross-cross method.
Subtract 7: \(-5x < 25\) → Divide by \(-5\) → \(\mathbf{x > -5}\)
Graph: Open circle at \(-5\), shade RIGHT.
Problem 3: \(4x - 9 \ge -1\) KEEP!
Add 9: \(4x \ge 8\) → Divide by \(+4\) → \(\mathbf{x \ge 2}\)
Graph: Closed circle at \(2\), shade RIGHT.
Teacher Script for the "Aha!" Moment:
"Class, think about temperature. Is 4 degrees colder or warmer than 10 degrees? Colder (\(4 < 10\)). Now what happens when we divide both by \(-2\): is \(-2\) degrees colder or warmer than \(-5\) degrees? \(-2\) is warmer! It is closer to melting! That's why whenever you divide by a negative number, the smaller magnitude becomes the greater value. The entire line spins 180 degrees around zero!"
23456
12. "A number \(x\) is at most −2" \(x\) ≤ -2
← →
-4-3-2-10
13. "A number \(x\) is fewer than 6" \(x\) < 6
← →
45678
14. "A number \(x\) exceeds −5" \(x\) > -5
← →
-7-6-5-4-3
15. \(x \ge 1.5\)
Circle: [ ] O [ ] • Arrow: [ ] ← [ ] →
← →
011.523
16. \(x < -2.5\)
Circle: [ ] O [ ] • Arrow: [ ] ← [ ] →
← →
-4-3-2.5-2-1
17. \(x > \frac{1}{2}\)
Circle: [ ] O [ ] • Arrow: [ ] ← [ ] →
← →
-101/212
18. \(x \le -\frac{3}{2}\)
Circle: [ ] O [ ] • Arrow: [ ] ← [ ] →
← →
-3-2-1.5-10
19. \(-7 < x\) → rewrite: \(x\) ___
Circle: [ ] O [ ] • Arrow: [ ] ← [ ] →
← →
-9-8-7-6-5
20. \(8 \ge x\) → rewrite: \(x\) ___
Circle: [ ] O [ ] • Arrow: [ ] ← [ ] →
← →
678910
✓ Self-Check Checklist: Did I use open circles for < / > and solid circles for ≤ / ≥? Did I reverse the sign when rewriting variable on left?
Final Mastery: / 20
(3) \(x \le -28\)
(4) \(x \ge 28\)
Step 1: Get rid of parentheses by Distributing & then place ALL terms (WITH SIGNS) into boxes & circles!
Circle Team (Move Right • Flip Sign!) →
← X-Box Team (Move Left • Flip Sign!)
X-Box
Circle
≤
X-Box
Circle
≤ "Cross the line... change the sign!" ≤
+ Moved X-Box
≤
+ Moved Circle
Combined X-Box:
≤
Combined Circle:
Final Step: Check the Coefficient of the Combined X-Box!
Divide both sides by the coefficient. IF IT IS NEGATIVE, FLIP THE INEQUALITY SYMBOL IMMEDIATELY! Watch out for \(-1x\) — dividing by \(-1\) flips the symbol!
Final Solution: X
?
Choice:
TI-Nspire Truth Test (Inequality Verification)
1. Pick test value: Try 0 → x (since \(0 \ge -28\)) • 2. Type original:3(x - 8) + 4x ≤ 8x + 4 • Press ENTER → Must display "true"!
Remind students that multiple choice questions can always be verified on the Nspire scratchpad. If a student is undecided between Choice (2) \(x \ge -28\) and Choice (3) \(x \le -28\), test \(x = 0\) (which is included in \(x \ge -28\) but NOT in \(x \le -28\)). Storing 0 → x and entering the original inequality returns "true", immediately confirming Choice (2)!