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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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Mental addition and subtraction (age 9+)

Mathematics · Addition & Subtraction · procedural

Add and subtract numbers mentally with increasingly large numbers, using place-value knowledge and derived facts

What mastery looks like

  • Mentally calculate 45,000 + 8,000
  • Mentally subtract 3,200 from 10,000 by counting up
  • Use near-doubles: 2,500 + 2,600 = 5,100

Check your understanding

Can Mental addition and subtraction (age 9+) work out something like '4,700 − 1,300' in their head using what they know about place value — without needing to write it all out?