Rule out wrong answers
Strategy card
Elimination turns a hard problem into several easy checks.
- Step 1: Identify a necessary condition (count, parity, symmetry, sign).
- Step 2: Apply it to every option.
- Step 3: Repeat with another condition until one option survives.
- Step 4: Verify the survivor fully; don't assume.
Tip: Quick checks such as units digits, parity, or symmetry often clear most options fast.
Worked example
Which figure completes the matrix?
- A: big striped green circle
- B: striped green diamond
- C: big green diamond
- D: big striped green triangle
- E: big striped green diamond (the answer)
Why: Each row keeps its own shape (triangle, circle, diamond, top to bottom). Every row has one of each fill (striped, outlined, solid), so the last row needs the one that is missing. Each column keeps its own size (small, medium, big, left to right). So the missing figure is the big striped green diamond.
Your turn
Your turn 1 of 3
germ is to illness as drought is to ___?
germ→illnessdrought→?
Your turn 2 of 3
Which number comes next?
3, 7, 15, 31, 63, 127, ?
Your turn 3 of 3
Which figure completes the matrix?
Keep practicing
Grown-ups: Talk about how detectives and doctors rule things out. Parent guide
Next lesson: Building equations