AI Constitution

Resources · Learning tool

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.

Sign in to track your progress and get personalized recommendations. You can browse freely below.

Knowledge-graph map

Computing
Mastered Ready to learn LockedHover a node for its description · click to open
Computers in Everyday L…Computers in Everyday Life — frontier Identifying computers in everyday life — not just laptops but phones, tablets, smart speakers, traffic lights, washing machines; what makes something a computerReal-World RobotsReal-World Robots — locked What a robot really is — not the sci-fi version; robots in factories, robot vacuum cleaners, robot arms in surgery; that robots follow instructions given by peopleSmart Versus Not-Smart…Smart Versus Not-Smart Devices — locked Sorting objects into 'smart' (can sense and respond) and 'not smart' (just sits there); a toaster vs a smart speaker; introduction to the idea that some machines can sense and respond to the worldStep-by-Step Instructio…Step-by-Step Instructions — locked Step-by-step instructions for everyday tasks (making a sandwich, brushing teeth); that if instructions are wrong or missing, things go wrong; computers follow instructions exactly
← Back

Adding two two-digit numbers

Mathematics · Addition & Subtraction · procedural

Add and subtract two two-digit numbers using concrete objects, pictorial representations, and mental methods

Sign in to track this

What mastery looks like

  • Calculate 34 + 27 using base-ten blocks or column addition
  • Calculate 63 − 28 using a number line or partitioning
  • Explain a strategy for adding or subtracting two two-digit numbers

Check your understanding

Can Adding two two-digit numbers add or subtract two two-digit numbers — like '43 + 28' — using counters, a drawing, or working it out in their head?

Prerequisites

Required first

Unlocks (1 directly)