Measuring Perimeters
PROCEDURALMeasure the perimeter of simple 2-D shapes
Mastery Evidence
- Measure each side of a rectangle and add the lengths to find the perimeter
- Calculate the perimeter of a regular shape given the side length
- Explain that perimeter is the total distance around a shape
Assessment Prompt
“If [child] wants to put a decorative border around a rectangular picture frame 20 cm wide and 30 cm tall, can they work out the total length of border needed?”
Curriculum Standards1 alignment
Ma/KS2/Y3/M/2The national curriculum in Englandmeasure the perimeter of simple 2-D shapes
Prerequisites2
- Calculating with measurementshardAges 7—8
- 2-D shapes (age 6+)softAges 6—7
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- 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
- 2-D shapes (age 6+) soft
Perimeter of 2-D shapes requires knowing shape properties (number of sides)
- Angles in triangles (age 6+) soft
Understanding defining attributes supports describing shape properties formally
- 2-D shapes hard
Distinguishing defining vs non-defining attributes requires knowing common 2-D shape names first
- 3-D shapes (age 5+) hard
Identifying defining attributes builds on informal analysis and comparison of shapes
- 2-D shapes hard
Describing properties of 2-D shapes (sides, symmetry) requires knowing the shapes first
- 3-D shapes (age 5+) hard
Formal property description extends informal analysis of sides and vertices
Unlocks1
- Perimeters of polygonshardAges 8—9