Factors, multiples, and primes

CONCEPTUAL

Mathematics›Multiplication & Division|Ages 9—11|ID: mt_FHIAv6dfhU

Find all factor pairs for a whole number in the range 1–100; identify common factors and common multiples of two numbers; use these concepts to solve problems

Mastery Evidence

List all factor pairs of 36: (1,36), (2,18), (3,12), (4,9), (6,6)
State the first five multiples of 7
Find the common factors of 24 and 36
Find all common factors of 36 and 48
Identify the first three common multiples of 6 and 8
Determine whether a given number (e.g. 97) is prime and justify the reasoning

Assessment Prompt

“Can [child] list all the factor pairs for a number like 36 — (1, 36), (2, 18), (3, 12), (4, 9), (6, 6) — and find factors that two numbers share?”

Prerequisites2

All times tables to 12×12
hardAges 8—9
Factor Pairs & Commutativity
hardAges 8—9

Show full prerequisite tree

All times tables to 12×12 hard
Tables to 12×12 fluency is prerequisite to finding factor pairs up to 100
- Counting in 6s soft
  Counting in 6s/7s/9s supports learning those table facts
  - Skip Counting (4s, 8s, 50s, 100s) hard
    Counting in 6s/7s/9s/25s/1000s extends counting in 4s/8s/50s/100s
    - Counting in 2s hard
      Counting in 4s and 8s extends prior skip counting in 2s, 5s, 10s
      - Rote counting to 100 hard
        Skip counting in 2s, 5s, 10s requires fluent rote counting by ones first
        
        One-to-one counting hard
        One-to-one correspondence requires knowing the number name sequence
- Times tables (age 7+) hard
  All tables to 12×12 extends knowledge of 3/4/8 tables
  - Times tables hard
    3, 4, 8 times tables build on known 2, 5, 10 tables
    - Counting in 2s hard
      Times tables for 2, 5, 10 build on skip counting in 2s, 5s, 10s
      - Rote counting to 100 hard
        Skip counting in 2s, 5s, 10s requires fluent rote counting by ones first
        
        One-to-one counting hard
        One-to-one correspondence requires knowing the number name sequence
    - Multiplication as repeated addition hard
      Recalling times table facts requires understanding multiplication as repeated addition/grouping
      - Counting in 2s soft
        Skip counting supports understanding equal groups (2s, 5s, 10s)
        
        Rote counting to 100 hard
        Skip counting in 2s, 5s, 10s requires fluent rote counting by ones first
        
        One-to-one counting hard
        One-to-one correspondence requires knowing the number name sequence
      - Addition as combining or putting together two hard
        Multiplication as repeated addition requires understanding addition as combining groups
        
        How Many in Total? hard
        Understanding addition as combining groups requires knowing numbers represent quantities (cardinality)
        
        One-to-one counting hard
        Cardinality principle builds on one-to-one correspondence — you must count correctly to know the last number tells 'how many'
  - Skip Counting (4s, 8s, 50s, 100s) soft
    Counting in 4s and 8s supports learning those table facts
    - Counting in 2s hard
      Counting in 4s and 8s extends prior skip counting in 2s, 5s, 10s
      - Rote counting to 100 hard
        Skip counting in 2s, 5s, 10s requires fluent rote counting by ones first
        
        One-to-one counting hard
        One-to-one correspondence requires knowing the number name sequence
Factor Pairs & Commutativity hard
Recognising factor pairs at Y4 is prerequisite to systematically finding all factor pairs
- All times tables to 12×12 hard
  Finding factor pairs requires fluent table knowledge
  - Counting in 6s soft
    Counting in 6s/7s/9s supports learning those table facts
    - Skip Counting (4s, 8s, 50s, 100s) hard
      Counting in 6s/7s/9s/25s/1000s extends counting in 4s/8s/50s/100s
      - Counting in 2s hard
        Counting in 4s and 8s extends prior skip counting in 2s, 5s, 10s
        
        Rote counting to 100 hard
        Skip counting in 2s, 5s, 10s requires fluent rote counting by ones first
        
        One-to-one counting hard
        One-to-one correspondence requires knowing the number name sequence
  - Times tables (age 7+) hard
    All tables to 12×12 extends knowledge of 3/4/8 tables
    - Times tables hard
      3, 4, 8 times tables build on known 2, 5, 10 tables
      - Counting in 2s hard
        Times tables for 2, 5, 10 build on skip counting in 2s, 5s, 10s
        
        Rote counting to 100 hard
        Skip counting in 2s, 5s, 10s requires fluent rote counting by ones first
        
        One-to-one counting hard
        One-to-one correspondence requires knowing the number name sequence
      - Multiplication as repeated addition hard
        Recalling times table facts requires understanding multiplication as repeated addition/grouping
        
        Counting in 2s soft
        Skip counting supports understanding equal groups (2s, 5s, 10s)
        
        Rote counting to 100 hard
        Skip counting in 2s, 5s, 10s requires fluent rote counting by ones first
        
        One-to-one counting hard
        One-to-one correspondence requires knowing the number name sequence
        
        Addition as combining or putting together two hard
        Multiplication as repeated addition requires understanding addition as combining groups
        
        How Many in Total? hard
        Understanding addition as combining groups requires knowing numbers represent quantities (cardinality)
        
        One-to-one counting hard
        Cardinality principle builds on one-to-one correspondence — you must count correctly to know the last number tells 'how many'
    - Skip Counting (4s, 8s, 50s, 100s) soft
      Counting in 4s and 8s supports learning those table facts
      - Counting in 2s hard
        Counting in 4s and 8s extends prior skip counting in 2s, 5s, 10s
        
        Rote counting to 100 hard
        Skip counting in 2s, 5s, 10s requires fluent rote counting by ones first
        
        One-to-one counting hard
        One-to-one correspondence requires knowing the number name sequence
- Properties of Operations soft
  Using commutativity in factor pairs draws on properties understanding
  - Commutative Multiplication hard
    Applying all three properties extends Y2 commutativity understanding
    - Arrays for multiplication soft
      Arrays help demonstrate commutativity (rotate the array)
      - Division as equal sharing hard
        Using arrays for division requires understanding division as grouping
        
        Subtraction as taking away or separating hard
        Division as equal sharing/grouping requires understanding subtraction as taking away/separating
        
        How Many in Total? hard
        Understanding subtraction as taking away requires knowing numbers represent quantities (cardinality)
        
        One-to-one counting hard
        Cardinality principle builds on one-to-one correspondence — you must count correctly to know the last number tells 'how many'
      - Multiplication as repeated addition hard
        Using arrays requires understanding what multiplication means
        
        Counting in 2s soft
        Skip counting supports understanding equal groups (2s, 5s, 10s)
        
        Rote counting to 100 hard
        Skip counting in 2s, 5s, 10s requires fluent rote counting by ones first
        
        One-to-one counting hard
        One-to-one correspondence requires knowing the number name sequence
        
        Addition as combining or putting together two hard
        Multiplication as repeated addition requires understanding addition as combining groups
        
        How Many in Total? hard
        Understanding addition as combining groups requires knowing numbers represent quantities (cardinality)
        
        One-to-one counting hard
        Cardinality principle builds on one-to-one correspondence — you must count correctly to know the last number tells 'how many'
    - Multiplication as repeated addition hard
      Commutativity of multiplication requires understanding multiplication
      - Counting in 2s soft
        Skip counting supports understanding equal groups (2s, 5s, 10s)
        
        Rote counting to 100 hard
        Skip counting in 2s, 5s, 10s requires fluent rote counting by ones first
        
        One-to-one counting hard
        One-to-one correspondence requires knowing the number name sequence
      - Addition as combining or putting together two hard
        Multiplication as repeated addition requires understanding addition as combining groups
        
        How Many in Total? hard
        Understanding addition as combining groups requires knowing numbers represent quantities (cardinality)
        
        One-to-one counting hard
        Cardinality principle builds on one-to-one correspondence — you must count correctly to know the last number tells 'how many'
  - What Multiplication Means hard
    Using properties requires understanding what multiplication means
    - Arrays for multiplication (age 7+) hard
      Extends array-based repeated addition to formal multiplication interpretation
      - Arrays for multiplication hard
        Rectangular arrays with repeated addition extends array representation from Y2
        
        Division as equal sharing hard
        Using arrays for division requires understanding division as grouping
        
        Subtraction as taking away or separating hard
        Division as equal sharing/grouping requires understanding subtraction as taking away/separating
        
        How Many in Total? hard
        Understanding subtraction as taking away requires knowing numbers represent quantities (cardinality)
        
        One-to-one counting hard
        Cardinality principle builds on one-to-one correspondence — you must count correctly to know the last number tells 'how many'
        
        Multiplication as repeated addition hard
        Using arrays requires understanding what multiplication means
        
        Counting in 2s soft
        Skip counting supports understanding equal groups (2s, 5s, 10s)
        
        Rote counting to 100 hard
        Skip counting in 2s, 5s, 10s requires fluent rote counting by ones first
        
        One-to-one counting hard
        One-to-one correspondence requires knowing the number name sequence
        
        Addition as combining or putting together two hard
        Multiplication as repeated addition requires understanding addition as combining groups
        
        How Many in Total? hard
        Understanding addition as combining groups requires knowing numbers represent quantities (cardinality)
        
        One-to-one counting hard
        Cardinality principle builds on one-to-one correspondence — you must count correctly to know the last number tells 'how many'
      - Multiplication as repeated addition hard
        Expressing array totals as sums of equal addends requires understanding multiplication as repeated addition
        
        Counting in 2s soft
        Skip counting supports understanding equal groups (2s, 5s, 10s)
        
        Rote counting to 100 hard
        Skip counting in 2s, 5s, 10s requires fluent rote counting by ones first
        
        One-to-one counting hard
        One-to-one correspondence requires knowing the number name sequence
        
        Addition as combining or putting together two hard
        Multiplication as repeated addition requires understanding addition as combining groups
        
        How Many in Total? hard
        Understanding addition as combining groups requires knowing numbers represent quantities (cardinality)
        
        One-to-one counting hard
        Cardinality principle builds on one-to-one correspondence — you must count correctly to know the last number tells 'how many'
    - Multiplication as repeated addition hard
      Interpreting products formalises repeated addition/equal groups from Y1
      - Counting in 2s soft
        Skip counting supports understanding equal groups (2s, 5s, 10s)
        
        Rote counting to 100 hard
        Skip counting in 2s, 5s, 10s requires fluent rote counting by ones first
        
        One-to-one counting hard
        One-to-one correspondence requires knowing the number name sequence
      - Addition as combining or putting together two hard
        Multiplication as repeated addition requires understanding addition as combining groups
        
        How Many in Total? hard
        Understanding addition as combining groups requires knowing numbers represent quantities (cardinality)
        
        One-to-one counting hard
        Cardinality principle builds on one-to-one correspondence — you must count correctly to know the last number tells 'how many'

Unlocks6

Factors, multiples, and primes (age 9+)
hardAges 9—10
Simplifying Fractions
hardAges 10—11
Fractions, Decimals & Percentages
softAges 9—10
Factors, multiples, and primes (age 11+)
hardAges 11—12
Ratio Notation
hardAges 11—12
Prime numbers
hardAges 9—10