Patterns and sorting · Grade RR
In Grade RR you learn: sorting objects by colour, shape and size; repeating patterns.
A pattern is something that repeats, or grows by a rule we can spot. Sorting means putting things into groups by what they have in common, such as colour, shape, size or number. Spotting patterns and rules is how mathematicians predict what comes next.
Key facts
- Find the part that repeats (the repeating unit), then keep it going.
- Say a pattern out loud: red, blue, blue, red, blue, blue …
- To find the 10th item, count on through the repeats, or use the length of the repeating unit.
- A number pattern has a rule, like add 2 each time or take away 5 each time.
- To sort, choose one rule (colour, shape, size, even or odd) and check every item against it.
- Something that breaks the rule is the odd one out.
Worked examples
Example 1
Red, blue, blue, red, blue, blue, red, … What comes next?
Answer: blue
Example 2
A bead pattern goes green, yellow, green, yellow, … What colour is the 9th bead?
Answer: green