Teacher copy: This page may include teaching prompts or answer keys. Answer keys in this public library can be viewed by anyone. Give learners a clean prompt, use checks as formative evidence, and change a case locally when prior access matters.
Goal: compare 10 and 18 despite different spacing and verify a material count. Proposed codes: AC9MFN01, AC9MFN03. Prepare: C4, optional C5, Card 149.
Warm · 3 min. Show two rows with different spacing; ask whether row length alone answers how many.
Model · 4 min. Put widely spaced A tiles into ten indexed places and crowded B tiles into 18 places; name every tile once.
Guide · 5 min. Child matches or counts to check B has more, then explains why spacing misled a first guess.
Independent route · 7 min. Child chooses book display, maker holder or paper theatre; records counts in two formats and says what count does not establish about design quality.
Zero check · 4 min. If ready, use C5 to show 20 used and no spare; count the empty supply as zero, without demanding subtraction notation.
Exit · 2 min. Child names a strategy for a fresh arrangement tomorrow. Keep Day 150 sets covered.