Metric & Imperial Conversion
CONCEPTUALUnderstand and use approximate equivalences between metric units and common imperial units (inches, pounds, pints)
Mastery Evidence
- State that 1 inch ≈ 2.5 cm and use this to estimate length in inches
- Know that 1 kg ≈ 2.2 pounds and estimate a person's weight in pounds
- Convert approximately between litres and pints (1 litre ≈ 1.75 pints)
Assessment Prompt
“If [child] hears that a baby weighs 7 pounds, can they give a rough idea of that in kilograms — using the approximate conversion they know?”
Prerequisites1
- Converting measurement units (age 9+)hardAges 9—10
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- Converting measurement units (age 9+) hard
Must know metric units before approximating imperial equivalences
- Converting measurement units hard
Y4 unit conversion is prerequisite to systematic metric conversions with tables
- Calculating with measurements hard
Measuring in standard units is prerequisite to converting between units
- Comparing and ordering measurements hard
Extends comparing/ordering measures to adding/subtracting them
- Choosing measurement units hard
Comparing and ordering measurements with symbols requires being able to measure in standard units
- Capacity and volume hard
Using standard units for capacity extends from beginning to measure capacity
- Comparing Capacity hard
Measuring capacity with units requires first being able to compare capacities
- Measurable Attributes of Objects hard
Comparing capacity requires understanding capacity as a measurable attribute
- Measuring length and height (age 5+) hard
Using standard units for length extends from 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
- Measuring mass and weight (age 4+) hard
Measuring mass with units requires first being able to compare masses directly
- Measurable Attributes of Objects hard
Comparing mass/weight requires first identifying mass as a measurable attribute
- The two digits of a two-digit number hard
Comparing two-digit numbers 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)
- Two written numerals between 1 and 10 soft
Comparing two-digit numbers extends from comparing single-digit written numerals
- Comparing groups: more or fewer soft
Comparing written numerals is the symbolic form of comparing quantities — conceptual comparison helps but isn't strictly required
- Counting objects to 20 soft
Counting a set helps when comparing groups, but younger children (GB age 4) can compare using matching without formal counting to 20
- 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'
- Choosing measurement units hard
Extends Y2 standard unit measurement to include mm and to add/subtract measures
- Capacity and volume hard
Using standard units for capacity extends from beginning to measure capacity
- Comparing Capacity hard
Measuring capacity with units requires first being able to compare capacities
- Measurable Attributes of Objects hard
Comparing capacity requires understanding capacity as a measurable attribute
- Measuring length and height (age 5+) hard
Using standard units for length extends from 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
- Measuring mass and weight (age 4+) hard
Measuring mass with units requires first being able to compare masses directly
- Measurable Attributes of Objects hard
Comparing mass/weight requires first identifying mass as a measurable attribute
- Time Units and Calendar Facts hard
Knowing seconds/minute, days/month etc. is prerequisite to unit conversion problems
- 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
- Dividing by 10 and 100 hard
Dividing by 10/100 (Y4 fractions context) is prerequisite to ×÷ by 10/100/1000 with decimals
- Finding halves and quarters (age 5+) hard
Working with 1/4, 2/4, 3/4 extends from Y1 understanding of quarters
- What Is a Half? hard
Understanding quarters extends from understanding halves — both are equal parts but quarters requires dividing into 4
- 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)
- 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'
- 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'
- Fraction Notation hard
Writing fractions like 1/3 and 3/4 requires knowing numerator and denominator
- Decimal equivalents of tenths and hundredths hard
Must know decimal notation to express results of dividing by 10/100
- Finding halves and quarters (age 5+) hard
Working with 1/4, 2/4, 3/4 extends from Y1 understanding of quarters
- What Is a Half? hard
Understanding quarters extends from understanding halves — both are equal parts but quarters requires dividing into 4
- 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
- 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)
- 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'
- Fraction Notation hard
Writing fractions like 1/3 and 3/4 requires knowing numerator and denominator
- Decimal & Percent Notation hard
Writing decimal equivalents of tenths and hundredths requires decimal point and place-value vocabulary
- Place value of each digit hard
Four-digit place value is prerequisite to understanding ×10 relationship between places
- The three digits of a three-digit number hard
Four-digit place value extends three-digit place value
- 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 two digits of a two-digit number hard
Must understand two-digit place value before extending to hundreds
- 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)
- 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)
- 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
- Miles & KilometreshardAges 10—11