A1.1 Stage 1–2 Algebra

Repeating patterns & sequences

Copy, continue & create repeating patterns/sequences (numbers, shapes, images); describe the rule.

A repeating pattern is a small unit that repeats over and over in a fixed order. This concept is about spotting that unit, continuing it, making your own — and putting the rule into words.

What it means

A pattern is any arrangement that follows a rule. A repeating pattern is the simplest kind: one chunk, called the core (or unit), copied again and again. In red-blue-red-blue-red-blue the core is “red, blue” and it just keeps repeating. Once you know the core, you know everything that comes next.

A sequence is a list of things in order — shapes, colours, pictures or numbers — such as 2, 4, 6, 8. Repeating patterns are one family of sequence; the order never changes, so the same items come round again and again like beads on a loop.

Four skills sit inside this can-do statement. Copying means reproducing a pattern you are shown, item for item. Continuing means carrying it on correctly — you must first find the core, then repeat it. Creating means inventing your own and keeping it consistent. Describing the rule means saying, in words, what the core is and how it repeats: “the shapes go circle, square, circle, square” or “each number is two more than the one before”.

People label the core with letters to talk about its shape. AB means two items alternating (red, blue, red, blue). ABB means one of the first then two of the second (red, blue, blue, red, blue, blue). ABC means three items in a cycle. The letters describe the structure, so any AB pattern — red/blue, up/down, clap/stamp — shares the same rule even with different pieces.

A key trick: to continue a pattern, find where the core ends and starts again, then just repeat it. To describe it, name the core and say “repeat”.

Worked examples

Continue a shape pattern. ● ▲ ● ▲ ● ▲ __ __ The core is ● ▲. It repeats, so the next two are ● ▲.

Find the core, then predict far ahead. In the pattern below, what is the 10th shape?

core:  ■ ● ●   (length 3)
1:■  2:●  3:●  4:■  5:●  6:●  7:■  8:●  9:●  10:■

Every 3rd position finishes a core, so positions 3, 6, 9 end one — position 10 starts a fresh core with .

A number sequence. 3, 5, 7, 9, … The rule is “start at 3, add 2 each time”. Next: 11. Here the core isn’t a repeated chunk but a repeated step (+2).

Describe your own. clap, clap, stamp, clap, clap, stamp … Rule: “the core is clap-clap-stamp, and it repeats.”

The generative-art connection

A repeating pattern is a rule, and generative art is what you get when you hand a rule to a machine and let it repeat. That is the whole seam of mathartcademy: the pattern you describe in words becomes something you can watch build itself.

In dot-multiplier, one dot is copied at equal turns around a circle. “Place a dot, rotate, repeat” is an AB-style rule wrapped into a ring, and the repetition is what produces the symmetric starburst — same core, many copies. In Pattern Shapes (Math Learning Center) a child drags tiles to lay a core down a strip and continue it by hand, seeing directly how one unit tiles a line. A frieze border — the repeating band around a plate or a page — is an AB or ABC core marched sideways forever. Change the core and the whole strip changes: this is exactly “create a pattern and describe the rule”, made visible.

Common misconceptions

  • Copying by length, not by rule. A child continues ●▲●▲ by adding “two more shapes” without checking which — write the core underneath and match position to position.
  • Losing the core across the wrap. In ABB (●▲▲) it is easy to slip into AB. Circle the core so the eye knows where it restarts.
  • “Pattern” means pretty, not rule-based. A pattern isn’t decoration — it is something with a rule you can state and use to predict what comes next. If you can’t say the rule, you haven’t found the pattern yet.

What a learner should be able to solve

The benchmark for mastering this concept — the problems a child at this stage is expected to be able to work through.

  1. Here is a repeating pattern: `square, circle, triangle, square, circle, triangle, __ , __ , __`. Draw or name the next three shapes, then say the rule in words.

    Answer

    Next three: `square, circle, triangle`. The core is `square, circle, triangle` (an ABC core, length 3) and it just repeats. The 6th item (triangle) finishes a core, so a fresh core starts again with square, circle, triangle.

    Art hook Place the ABC core on a strip of 3 colour swatches, then tile it rightward across a Canvas row; a slider sets how many times the core repeats so the child watches the same 3-colour unit march across the screen.

  2. A pattern goes `red, blue, blue, red, blue, blue, ...`. What colour is the `9th` bead? Explain how you know without drawing all nine.

    Answer

    `Blue`. The core is `red, blue, blue` (length 3). Positions 3, 6 and 9 are each the last bead of a core (`9 = 3 × 3`), and the core ends in blue, so the 9th bead is blue.

    Art hook Draw N beads on a circle (a loop necklace). Colour them by an ABB rule as you go around; a counter highlights every 3rd bead so the child sees the core landing at positions 3, 6, 9.

  3. Make up your own repeating pattern using two body actions (like clap and jump). Write out at least two full copies of your core, then write the rule.

    Answer

    Any consistent core repeated works, e.g. AB `clap, jump, clap, jump` or ABB `clap, jump, jump, clap, jump, jump`. Success = the core repeats exactly with no changes, and the rule names the core, e.g. 'the core is clap-jump-jump and it repeats.'

    Art hook Turn each action into a Canvas symbol (open dot = clap, filled square = jump). The child's typed sequence draws itself as a row of symbols, and a 'play' button pulses each symbol in time like a rhythm strip.

  4. Look at this number sequence: `5, 8, 11, 14, __`. What number comes next, and what is the rule?

    Answer

    Next is `17`. The rule is 'start at 5, add 3 each time' (`+3`), so `14 + 3 = 17`. Here the repeating part is the step (+3), not a repeated chunk.

    Art hook Draw a number line and light up dots at 5, 8, 11, 14, 17 as equal jumps of 3; each jump is an arc of the same width, so the repeating step becomes a repeating visual hop.

  5. Someone tried to continue `circle, star, circle, star, ...` but wrote `circle, star, circle, star, star, circle`. Find the mistake and fix it.

    Answer

    The mistake is the extra `star`. The core is `circle, star` (AB). After the 4th item (star) the core should restart with circle. Correct continuation: `circle, star, circle, star, circle, star`.

    Art hook Show two rows on a Canvas: the wrong pattern and a slot to fix it. Each square that breaks the AB rule flashes red until the child sets it to the colour the rule predicts, then turns green.

Training exercises

Practice problems, easier first, that build toward the bar above. Each doubles as a seed for an interactive artwork.

  1. Copy this pattern exactly, item for item: `▲ ▲ ● ▲ ▲ ●`. What did you copy?

    Answer

    An exact copy: `▲ ▲ ● ▲ ▲ ●`. Copying means reproducing each item in the same order, not changing or adding any.

    Art hook A 'mirror strip' on Canvas: the top row is fixed and the child clicks empty squares below to rebuild it. When their row matches item-for-item, the whole strip glows.

  2. Continue this pattern for two more shapes: `● ■ ● ■ ● ■ __ __`.

    Answer

    `● ■`. The core is `● ■` (AB) and it repeats, so the next two are circle then square.

    Art hook Draw dots and squares alternating around a circle instead of a line; the AB rule becomes a two-colour ring, like a simple dot-multiplier necklace.

  3. What is the core (the part that repeats) in this pattern? `yellow, green, green, yellow, green, green, yellow, green, green`

    Answer

    The core is `yellow, green, green` (an ABB core, length 3). Every group of three is one copy of it.

    Art hook Colour a row of 9 Canvas squares by the rule, then draw a bracket that snaps around each group of 3 to show the repeating unit.

  4. Continue this ABB pattern for three more items: `clap, stamp, stamp, clap, stamp, stamp, __ , __ , __`.

    Answer

    `clap, stamp, stamp`. The core is clap-stamp-stamp (length 3) and it repeats.

    Art hook A rhythm bar where each beat is a dot; claps are big dots, stamps are small dots. The child adds beats and the bar plays back the repeating clap-stamp-stamp groove.

  5. Continue this ABC colour pattern for three more: `red, yellow, blue, red, yellow, blue, __ , __ , __`.

    Answer

    `red, yellow, blue`. The core is `red, yellow, blue` (length 3) and it repeats.

    Art hook Take 3 slices of a colour wheel (red, yellow, blue) and stamp them repeatedly around a ring so the ABC core becomes a spinning three-colour pinwheel.

  6. Continue this number sequence: `2, 4, 6, 8, __, __`. What is the rule?

    Answer

    `10, 12`. The rule is 'add 2 each time' (`+2`) — this is counting in twos, which lists the even numbers.

    Art hook A number line where each step of +2 draws an equal-size hop; colour the landing dots (2, 4, 6, 8, 10, 12) to reveal a repeating stripe of evens.

  7. Continue this number sequence and name the rule: `10, 20, 30, 40, __`.

    Answer

    `50`. The rule is 'start at 10, add 10 each time' (`+10`) — counting in tens.

    Art hook Stack 10 dots per column and add one column each step; the growing bar chart shows 10, 20, 30, 40, 50 as equal jumps of a full ten-dot column.

  8. A pattern is `A, B, C, A, B, C, ...`. What is the `7th` letter? Try to answer without writing all seven.

    Answer

    `A`. The core `A, B, C` has length 3, so positions 3 and 6 each finish a core; position 7 starts a fresh core with A.

    Art hook Place 12 dots evenly on a circle and label them 1-12; colour them by the ABC rule so the same three colours repeat, and highlight dot 7 to show it lands back on A.

  9. Spot the mistake: someone continued `up, down, up, down, ...` as `up, down, up, down, down, up`. What went wrong, and what should it be?

    Answer

    The extra `down` breaks the AB core. After 'down' the core restarts with 'up'. Correct: `up, down, up, down, up, down`.

    Art hook An arrow strip on Canvas: up-arrows and down-arrows. The square that breaks the AB rule shakes and turns red until the child flips it to match; correct arrows settle into a smooth zig-zag.

  10. Invent your own ABC repeating pattern using three different shapes. Write two full copies of your core, then describe the rule in words.

    Answer

    Any consistent 3-item core repeated works, e.g. `heart, square, circle, heart, square, circle`. Success = the three-item core repeats with no change, and the rule names it: 'the core is heart-square-circle and it repeats.'

    Art hook A build-your-own tiler: the child picks 3 shapes for a core, and Canvas tiles that core across a strip and also wraps it around a ring, so one invented rule produces both a border and a rosette.

  11. Reasoning challenge: in the pattern `▲ ● ● ▲ ● ● ...`, will position `12` be a triangle or a circle? Explain.

    Answer

    A `circle`. The core is `▲ ● ●` (length 3). Positions 3, 6, 9 and 12 are all the last item of a core (`12 = 3 × 4`), and the core ends with a circle, so position 12 is a circle.

    Art hook Draw 12 dots on a circle and colour them by the ABB rule going round; mark every 3rd dot to show the core closing, revealing that dot 12 lands on the '●' end.