Comparing lengths by measuring

PROCEDURAL

Mathematics›Measurement|Ages 7—8|ID: mt_xWg0lI_gG4

Measure to determine how much longer one object is than another, expressing the length difference in terms of a standard length unit

Mastery Evidence

Measure two objects and calculate the difference in length
Express the difference using the correct unit (e.g. '7 cm longer')
Solve a comparison problem: 'How much taller is the bookshelf than the desk?'

Assessment Prompt

“If a pencil is 16 cm and a crayon is 9 cm, can [child] work out how much longer the pencil is — without measuring them side by side?”

Curriculum Standards1 alignment

2.MD.4Common Core State Standards for Mathematics

Compare lengths of objects

Measure to determine how much longer one object is than another, expressing the length difference in terms of a standard length unit.

Measurement and Data

Prerequisites2

Measuring length (age 7+)
hardAges 7—8
Measuring length
hardAges 6—7

Show full prerequisite tree

Measuring length (age 7+) hard
Comparing measured lengths requires ability to measure with tools
- Measuring length (age 6+) hard
  Using standard measurement tools extends measuring with non-standard units
  - 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
  - Measuring length soft
    Measuring with units benefits from ability to order and compare lengths
    - 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
- Choosing measurement units soft
  Choosing appropriate tools builds on choosing appropriate 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 hard
    Using standard units for mass extends from beginning to measure mass
    - 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
Measuring length hard
Extends ordering/comparing by length to expressing differences in standard units
- 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

Unlocks1

Addition and subtraction word problems
hardAges 7—8