Model finding an unknown using the balance idea: 25 + □ = 40 means "what added to 25 makes 40?" — use the inverse, 40 − 25 = 15. Then explore a multiplication pattern (3, 6, 9, 12…) and ask what comes next and why.
Together 1. Find the leaf-covered number: □ + 18 = 30.
Together 2. Continue the pattern 4, 8, 12, 16, … and describe the rule.
Students complete "Ollie's Leaf Puzzles: Patterns & Missing Numbers".