Spot the rule in a series
One clear pattern beats guessing.
← All countdown tipsSeries questions show a line of shapes that change by one clear rule. Your job is to spot what actually changes in every step — shade count, rotation, size, or position — then choose the next (or missing) frame that keeps the same rule going.
Picture it: one rule across the line
- Name the rule in a short sentence before you look at the options
- Check that the same rule fits every step, not just the first two
- If two things seem to change, decide which one is the real pattern
Remember — the method
- Compare frame 1 → 2: what moved, grew, turned, or filled in?
- Test that change on frame 2 → 3. If it breaks, try a different attribute.
- Apply the surviving rule to find the next (or missing) frame.
- Reject options that only fit the start of the series.
What might be changing?
Run through this checklist on every series. Usually only one attribute steps steadily — the rest is decoration.
Shade count
+1 / −1 filled cells
Rotation step
Same shape, turns by a fixed angle
Size
Grows or shrinks by a steady step
Position in a grid
A mark walks cell by cell
Number of sides
Triangle → square → pentagon…
Fill pattern
Solid → striped → dotted (or cycles)
Coach habit
Point to each frame and say the rule aloud. If you stumble on one frame, the rule is wrong — try the next attribute on the checklist.
Exam trap
Distractors that fit the first two frames, then break. Children stop checking after step 1 → 2 and pick a lookalike that fails later in the series.
Looks like “+1 shade” early on — but frame 3 proves the real rule is a clockwise move of the shaded cell
Question patterns you might see
Same skill, harder outfits — from a single changing attribute to multi-attribute decoys.
1 · Simple — Shade count
Each frame adds one more shaded cell. Which option continues the series?
2 · Simple — Rotation step
An arrow turns 90° clockwise each frame. Track the tip only — that is enough.
3 · Simple — Size step
Circles grow by a steady amount each frame. The next one is larger again — not a return to the small start.
4 · Medium — Position in a grid
A dot walks one cell right each frame (and wraps to the next row when needed). Follow the path, not the empty cells.
5 · Medium — Number of sides
Each frame adds one side: triangle → square → pentagon. Count sides — colour and size can be red herrings.
6 · Medium — Fill pattern cycle
Fill cycles solid → stripes → dots → solid… Shape stays the same. Find where the cycle lands next.
7 · Trickier — Distractor that fits two frames
Option A continues “+1 side” which works for triangle → square, but the real series is “rotate the same shape”. Always check frame 3 before you commit.
8 · Trickier — Multiple attributes change
Size and fill seem to change. Only one attribute follows a steady rule across all frames — the other is decoration. Find what actually steps the same way each time.
9 · Trickiest — Missing middle frame
Frames 1, 2, 4, and 5 are given; frame 3 is blank. Work the rule both forwards from the start and backwards from the end — they must meet.
10 · Trickiest — Two-step alternating rule
Odd steps add a shade; even steps rotate 90°. Write both half-rules, then apply the next one in order.
Coach tip: write the rule in five words or fewer (“+1 shade”, “90° turn”, “dot moves right”). If you cannot say it that short, you have not found it yet.
Tomorrow (D-21): letter codes & shifts.
Next step
Practice locks the idea in. WhatsApp delivers tomorrow’s tip to your phone — same group as mock updates.