Numbers on a number line

PROCEDURAL

Mathematics›Measurement|Ages 8—9|ID: mt_IL86kadLSS

Solve word problems involving elapsed time by adding and subtracting time intervals in minutes, including using a number line

Mastery Evidence

A film starts at 2:15 and lasts 47 minutes — when does it end?
Calculate how many minutes between 9:20 and 10:05
Use a number line to show the elapsed time between two events

Assessment Prompt

“If [child] starts football practice at 3:20 p.m. and it lasts 75 minutes, can they work out what time it finishes — using a number line to help?”

Prerequisites2

Comparing Time Durations
hardAges 7—8
Telling time to the minute (age 8+)
hardAges 8—9

Show full prerequisite tree

Comparing Time Durations hard
Prior duration comparison experience feeds into elapsed-time problem solving
- Estimating answers (age 7+) hard
  Calculating event durations requires reading time to the minute
  - Telling time to the minute (age 7+) hard
    Reading to nearest minute extends reading to five minutes
    - Telling Time: Minutes hard
      Extends telling time to include a.m./p.m. and 24-hour notation
      - Telling Time: Hours and Half Hours hard
        Telling time to 5 minutes extends from telling time to the hour and half past
        
        Reading and writing numbers to 20 hard
        Reading a clock requires recognising numerals 1–12
        
        How Many in Total? hard
        Reading/writing numerals 0–20 requires understanding that numerals 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'
        
        Writing digits 0-9 hard
        Writing numerals requires the motor skill of forming digits 0-9 (taught in English handwriting)
        
        Sitting and holding a pencil soft
        Same motor skills for digit formation
        
        What Is a Half? soft
        Understanding 'half past' benefits from the concept of halves
        
        Division as equal sharing hard
        Finding a half requires equal sharing into 2 groups — a division concept
        
        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'
        
        Telling time to the minute hard
        Telling time on a clock requires understanding hours and minutes as time units
        
        Comparing durations hard
        Measuring time in units requires understanding time comparison language first
      - Counting in 2s soft
        Reading 5-minute intervals benefits from skip counting in 5s
        
        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
  - Sequence intervals of time hard
    Extends comparing time intervals to recording in seconds, minutes, hours
    - Telling time to the minute hard
      Sequencing intervals requires understanding time measurement
      - Comparing durations hard
        Measuring time in units requires understanding time comparison language first
    - Comparing durations hard
      Comparing and sequencing intervals extends Y1 comparative time language
- Time Units and Calendar Facts soft
  Knowing time unit relationships supports duration calculations
  - Number of minutes in an hour hard
    Extends knowing minutes in an hour to seconds in a minute and days in months
    - Telling time to the minute hard
      Knowing 60 min = 1 hour and 24 hours = 1 day extends from measuring time in hours/minutes/seconds
      - Comparing durations hard
        Measuring time in units requires understanding time comparison language first
Telling time to the minute (age 8+) hard
Must read time to nearest minute before solving elapsed time problems
- Telling time to the minute (age 7+) hard
  Tell time to 5 minutes is prerequisite to telling time to nearest minute
  - Telling Time: Minutes hard
    Extends telling time to include a.m./p.m. and 24-hour notation
    - Telling Time: Hours and Half Hours hard
      Telling time to 5 minutes extends from telling time to the hour and half past
      - Reading and writing numbers to 20 hard
        Reading a clock requires recognising numerals 1–12
        
        How Many in Total? hard
        Reading/writing numerals 0–20 requires understanding that numerals 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'
        
        Writing digits 0-9 hard
        Writing numerals requires the motor skill of forming digits 0-9 (taught in English handwriting)
        
        Sitting and holding a pencil soft
        Same motor skills for digit formation
      - What Is a Half? soft
        Understanding 'half past' benefits from the concept of halves
        
        Division as equal sharing hard
        Finding a half requires equal sharing into 2 groups — a division concept
        
        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'
      - Telling time to the minute hard
        Telling time on a clock requires understanding hours and minutes as time units
        
        Comparing durations hard
        Measuring time in units requires understanding time comparison language first
    - Counting in 2s soft
      Reading 5-minute intervals benefits from skip counting in 5s
      - 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

Unlocks2

Telling time to the minute (age 9+)
hardAges 9—10
Choosing mathematical tools
softAges 8—9