Numbers on a number line
METASelect and use appropriate tools and representations (number lines, hundred squares, rulers, part-whole models) to support problem-solving
Mastery Evidence
- Choose a number line or hundred square to support adding or subtracting two-digit numbers
- Select a ruler when a problem requires measuring length
- Explain why one representation (e.g. a number line vs cubes) is more helpful for a particular problem
Assessment Prompt
“When [child] is tackling a maths problem, do they choose a useful tool — like a number line for addition or a hundred square to count on — rather than always working in their head?”
Prerequisites3
- Hands-On Problem SolvinghardAges 5—6
- Measuring length (age 6+)softAges 6—7
- Adding within 100softAges 6—7
Show full prerequisite tree
- Hands-On Problem Solving hard
Age 6-7 strategic tool selection builds on age 5-6 familiarity with basic tools
- Counting objects to 20 soft
Counting objects requires choosing appropriate tools (cubes, ten frames)
- 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'
- Measuring length (age 6+) soft
Measuring length with units requires selecting appropriate measurement tools
- Measuring length and height (age 5+) hard
Measuring with iterated units extends Y1 beginning to measure length
- Comparing Lengths & Heights hard
Measuring length with units requires first being able to compare lengths directly
- Measurable Attributes of Objects hard
Comparing lengths/heights requires first identifying length as a measurable attribute
- Comparing Lengths & Heights hard
Ordering 3 objects by length and indirect comparison extends direct length comparison
- Measurable Attributes of Objects hard
Comparing lengths/heights requires first identifying length as a measurable attribute
- Adding within 100 soft
Adding within 100 requires choosing number line vs hundred square strategically
- Addition and subtraction within 20 hard
Adding within 100 extends within-20 strategies to larger numbers
- Numbers up to 10 into pairs hard
Making 10 is a specific application of decomposing numbers into pairs
- Addition as combining or putting together two hard
Decomposing numbers into pairs requires understanding addition as combining
- 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'
- Fluent adding and subtracting within 10 hard
Strategies for within-20 calculation build on fluent within-10 knowledge
- Numbers up to 10 into pairs hard
Making 10 is a specific application of decomposing numbers into pairs
- Addition as combining or putting together two hard
Decomposing numbers into pairs requires understanding addition as combining
- 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'
- Addition as combining or putting together two hard
Fluency with addition within 5 requires understanding addition as combining
- 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'
- Subtraction as taking away or separating hard
Fluency with subtraction within 5 requires understanding subtraction as taking away
- 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'
- The two digits of a two-digit number hard
Adding within 100 using PV requires understanding tens and ones
- A Ten Is Ten Ones hard
Understanding tens and ones place value requires the concept of 10 as a bundle
- The teen numbers hard
Understanding 10 as a bundle builds on understanding teen numbers as 'a ten and some ones'
- How Many in Total? hard
Understanding tens-and-ones composition requires cardinality — knowing numbers represent quantities
- 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'
- Reading and writing numbers to 20 hard
Composing/decomposing teen numbers requires reading and writing those numerals
- 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)
- The teen numbers hard
General two-digit place value extends from understanding teen number composition
- How Many in Total? hard
Understanding tens-and-ones composition requires cardinality — knowing numbers represent quantities
- 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'
- Reading and writing numbers to 20 hard
Composing/decomposing teen numbers requires reading and writing those numerals
- 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)
Unlocks1
- Choosing the right strategyhardAges 7—8