What this pattern means
Each row (or each column, or both) contains the same total of each category. The per-cell counts vary freely as long as the row totals — and sometimes column totals — are invariant. The solver must deduce the missing cell's contribution to keep the invariant.
How to spot it
- Cells contain multi-category counts.
- The per-row sum of each category is identical across all three rows.
- The total per row is constant even though cell counts vary.
Common visual signals
- Group-counting questions with three or more visible categories.
- Row-2 cells appear to 'rebalance' what row-0 and row-1 already supplied.
- A double-conservation question may also constrain columns.
Step-by-step solving tactic
- 1Sum each row's total per category from the visible cells.
- 2Confirm that the row total is identical across the visible rows.
- 3For the missing cell, compute the row total minus the visible cells in that row.
- 4If both rows and columns are conserved, intersect both constraints.
Common traps
- Confusing conservation with addition — conservation keeps totals constant; addition grows them.
- Missing the second axis — double-conservation requires both rows AND columns.
- Nested conservation: per-row totals K_r themselves follow a meta-rule across rows.
Related patterns
Apply this pattern under timed conditions
Take the free 10-question matrix reasoning practice test — every question carries the conservation pattern or another commonly tested mechanic.