Rocket presses the last strip of tape flat so no one trips. The floor number line runs from 0 to 12.
"Puzzle Lab," he says. "I call a rule. You stand on a number that fits. Then we check it."
Raven reads the first card. "More than 5." Rocket jumps to the 9. "What do you notice about the 5?" she asks.
"I cannot stand on it," Rocket says. "Open circle." He drops a paper ring on the 5 and unrolls the ribbon right.
Nova hovers above the line, her light counting the tape marks. "Now try a rule with two steps," she says.
"Two steps?" Rocket asks. Raven grins. "Double your number, add 1, and it has to be less than 9."
Nova hums. "Stand somewhere, then test it before you cheer."
Tape a number line on the floor, call rules, and walk to a number that fits. Mark each rule with a circle and a ribbon.
Log every rule: the words, the inequality, where you stood, and whether the check came out true.
| Card | The rule | Inequality | Rocket stood on | Check |
|---|---|---|---|---|
| 1 | more than 5 | x > 5 | 9 | true |
| 2 | at most 3 | x ≤ 3 | 3 | true |
| 3 | less than 7 | x < 7 | 7 | false |
| 4 | at least 10 | x ≥ 10 | 11 | true |
| 5 | double it, add 1, less than 9 | 2x + 1 < 9 | 4 | false |
| 6 | double it, add 1, less than 9 | 2x + 1 < 9 | 2 | true |
These are the crew's own cards from Raven's log. On card 3 Rocket stood on the boundary, and the check came out false.
On card 5 he tried 4: 2 × 4 + 1 = 9, which is not less than 9. Card 6 was the retry with 2: 5 < 9. True.
Undoing both steps shows the whole set. Subtract 1, then divide by 2, and 2x + 1 < 9 becomes x < 4.
| Statement | True or false? |
|---|---|
| x = 7 makes x < 7 true. | ? |
| x = 10 makes x ≥ 10 true. | ? |
| x = 3.5 makes 2x + 1 < 9 true. | ? |
| Card 1 needs an open circle on the 5. | ? |
Six rules walked and checked. Tomorrow the crew solves two-step rules on paper, undoing on both sides.