math-tasks/tasks/cargo-filling/docs/cargo-filling-2.md

Cargo Filling — Document 2

Addition crossing the tens boundary (odd pages) and the twenties boundary (even pages). 10 pages, 6 cards per page, 60 problems total.

Same ships, asteroids, hero/footer images and element positions as Document 1 — only the numbers changed (positions are preserved via cargo-filling-2.data.json, copied from Doc 1; page 10 reuses page 2's layout).

Crossing rule (the only difference from Doc 1)

• Odd pages (1, 3, 5, 7, 9) — cross 10: cargo capacity badge = 10, A already in cargo (1–9), N = 10 − A, brace value 10.
• Even pages (2, 4, 6, 8, 10) — cross 20: cargo capacity badge = 20, A already in cargo (11–19), N = 20 − A, brace value 20.
• Floating asteroid B is always 1–9 on every page. The child splits B = N + M so A + N hits the boundary.
• Full expression: A + B = (A + N) + M = C.

Numbers are randomly spread: each page draws 6 distinct A values spread across the whole valid A-range, each paired with a varied B (preferring B values not yet used on the page). Only the constraints you set apply: asteroid B=1–9, capacity 10/20, crossing with non-zero fill N and non-zero remnant M. Generated with seeded RNG (mulberry32(20260622)) in /tmp/build-cf2.cjs so the set is reproducible.

Card 1 of page 1 is the worked example (answers filled in handwriting style): A=5, B=9 → N=5, M=4, C=14.

Numbers per page (A + B)

Page	Boundary	Problems (A+B)
1	10	5+9, 3+8, 4+7, 2+9, 6+6, 9+4
2	20	19+3, 17+4, 15+6, 18+7, 14+9, 12+9
3	10	3+8, 5+6, 6+7, 2+9, 8+5, 4+8
4	20	12+9, 18+3, 19+2, 14+9, 17+5, 16+7
5	10	9+2, 3+8, 5+7, 7+5, 8+3, 4+9
6	20	16+5, 14+7, 17+9, 12+9, 19+8, 15+6
7	10	5+6, 6+5, 7+7, 8+4, 3+8, 2+9
8	20	18+9, 12+9, 17+5, 19+3, 15+8, 13+9
9	10	8+6, 4+7, 5+9, 9+3, 6+5, 3+8
10	20	17+7, 18+6, 13+8, 16+9, 15+6, 19+2

Hero orientation

Odd pages = hero on the right (flex-row-reverse), even pages = hero on the left (matches Doc 1 convention). Page 10 reuses page 2's hero/footer (splitter6 / cabin3).