Concept 5 of 5
Shape Grids: Find the Missing Shape
Today's big idea
Each shape once per row and column
Cross out what's used — the survivor fits.
How it works
👀 What's going on?
A puzzle grid can be as strict as a Sudoku: every row and every column shows a circle, a square and a triangle exactly once, and never the same shape twice in a line. So if one cell is left blank, you can still name the shape that belongs there — the rule decides it.
💡 Here's the trick
Look at the grid above. Every row shows each shape once, and every column shows each shape once too. So the empty cell must be the one shape its row and its column are both missing.
- 1.Look across the gap's row. Which two shapes are already there?
- 2.Look down the gap's column. Which shape is still missing from both?
- 3.That leftover shape fills the gap.
✍️ Try it
Which shape fills the gap so every row and column shows each shape once?
?
The bottom row already has and , so it still needs . The last column agrees, so the gap is .
⚠️ Watch out
Do not fill the gap with whatever shape looks nice. Use the rule: each shape appears once per row and once per column. Read both before you choose.
See it in action
⚡ Time to play!
Every row and column shows each shape once. Work out the missing one and drag it into the gap.
Drag the missing shape into the gap
Quick check
✅ VERIFICATION
Which shape fills the gap so every row and column shows each shape once?
?
⚡ Finish the activity above first to answer.
Keep going!