One-to-one matching to 10
Match each visible object once, then use the unmatched objects to answer an exact count question.
Core · One-to-one match and count · Direct check · Finite-set matching count
Watch: Use this to watch whether the player places each same-badge card once, then counts only holders with no card.
Misread: Counts matched pairs or cards instead of target holders with no card.
Curriculum: Early one-to-one correspondence and cardinality within 10.