Line-of-Sight Sums: Swap Tiles Until Every Sight Line Adds Up
Generate fresh tile values, blocker placement, and row/column sight-sum targets.
The Blocker Ends the Line: Tiles Behind It Never Count
Generate fresh tile values, blocker placement, and row/column sight-sum targets. Swap tiles and stop counting after the first blocker; targets are derived from a legal complete arrangement.
Where Multi-Digit Addition Turns into Constraint Reasoning (Grades 4–7)
Players arrive fluent in multi-digit addition (4.NBT.B.4) and here apply it under constraints, holding several row and column conditions true at the same time. That constraint-satisfaction habit is the on-ramp to writing and reasoning about expressions and equivalent expressions (6.EE.B.5, 6.EE.B.6). It also sharpens the awareness that a total depends on what is included, not merely on which digits are present.
Learning Points
- spatial transformation
- multi-step planning
- working memory
- strategy review
Steps and completion rules
- Read from each arrow and locate the first blocker on that line.
- Calculate the current visible sum, then select two tiles to swap.
- Track changes to the current row and column sight sums until they match every fixed target.
Teacher / Parent Note
Predict which sight lines will change before swapping, and explicitly exclude numbers hidden behind a blocker.