Number Sequence

Choose a mode

Find the rule of the sequence (add or multiply), set the missing stone with the − / + buttons (or drag up to raise it), then press Check

3D math game · Best for grades 3-5

Number Sequence

Number Sequence places a row of numbered stones with one stone missing and asks students to figure out the rule — add the same amount each time, or multiply — then supply the missing value. It bridges visual pattern work toward rule-based arithmetic thinking for grades 3–5.

What students practice

Finding a rule from a sequence of numbers and applying it trains skip-counting, arithmetic-progression recognition, and early function thinking — skills that feed directly into multiplication tables, input-output tables, and pattern algebra in grades 3–5.

  1. Read all the visible numbers in the row and look for what changes between each pair.
  2. Decide whether the rule is additive (each step adds the same amount) or multiplicative (each step multiplies).
  3. Use the − / + buttons, or drag the missing stone upward, to set the correct value.
  4. Press Check to confirm your answer.

How to use it at home or in class

A sequence shows 3, 6, 9, ?, 15. Each step adds 3, so the missing number is 12. Seeing that the gap between each pair is equal — not just reading the last number — is the reasoning skill Number Sequence develops.

Students commonly guess by adding one more than the previous term instead of measuring the actual gap. Number Sequence requires checking multiple gaps to confirm the rule, training the habit of verifying before answering.

Use it for individual practice, paired work, or a short class demonstration before worksheets.

Start with the game above, then continue with written practice to reinforce the skill.

Common questions

How does the missing-stone mechanic teach rule-finding rather than just answer-guessing?
The stone appears anywhere in the sequence — not always at the end — so students must establish the rule from the surrounding terms rather than extending a list by one more step.
Which grades is Number Sequence for?
It suits grades 3–5, where students move from visual patterns to numeric rules and begin formalising arithmetic and multiplicative relationships.
How is Number Sequence different from Geometric Sequence?
Number Sequence mixes additive and simple multiplicative rules; Geometric Sequence focuses exclusively on constant-ratio multiplication such as ×2 or ×3 — the next level of difficulty.