Crystal Cavern
Master the Magic of Fact Families!
Deep within the Crystal Cavern, the ancient mathematical gems are missing their partners. Can you restore balance? This game teaches Fact Families (Inverse Relationships) in a visually intuitive way.
Designed for Year 2, it helps children see that if they know 7 + 3 = 10, they also know 10 - 3 = 7. The triangle layout reinforces the connection between the "Whole" (top) and the "Parts" (bottom).
⛏️ How to Play
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🔺
Read the Triangle Look at the three corners. The top number is the Total. The bottom two are the Parts.
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Find the Missing Link One corner is empty!
Is the top missing? Add the bottom numbers.
Is a bottom missing? Subtract the part from the top. -
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Place the Crystal Select the correct gem from your inventory to complete the family and light up the cave.
📚 Curriculum Focus (Number)
Crystal Cavern focuses on the "Inverse Relationship" objective:
- Part-Whole Model Visualize numbers as being made of smaller parts (e.g., 6 is made of 4 and 2).
- Inverse Operations Recognise and use the inverse relationship between addition and subtraction to check calculations.
- Missing Number Problems Solve equations with a missing value (e.g., ? + 7 = 10).
🧠 Why Triangles?
Linear equations (3 + 5 = 8) are one-directional. The Triangle Method shows that these three numbers are a family that belongs together forever.
It removes the fear of subtraction by showing it's just "addition backwards".
👨👩👧 Tips from the Miner
The Hiding Game:
- Get three post-it notes with a fact family (e.g., 2, 8, 10).
- Stick them in a triangle shape on the fridge.
- Hide one. Ask: "Who is missing?"
Excavated for Year 2 Mathematicians.
