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Education Concept Tracker

A prerequisite knowledge graph of 1590 learning concepts across 8subjects. Track what you've mastered and see exactly what you're ready to learn next — the topics whose prerequisites you've already met. Built on the Marble Open Skill Taxonomy.

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Comparing lengths by measuring

Mathematics · Measurement · procedural

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

What mastery looks like

  • 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?'

Check your understanding

If a pencil is 16 cm and a crayon is 9 cm, can Comparing lengths by measuring work out how much longer the pencil is — without measuring them side by side?