{
  "version": 1,
  "kind": "barmodel",
  "title": "Maya read 45 pages and Tom read 28. How many more did Maya read?",
  "description": "A comparison bar model: two bars on one left edge in one scale, Tom's shorter by a dashed difference marked with a question mark.",
  "bars": [
    {"id": "maya", "text": "Maya", "parts": [{"amount": 45}]},
    {"text": "Tom", "parts": [
      {"amount": 28},
      {"id": "more", "amount": 17, "text": "?", "role": "note"}
    ]}
  ],
  "braces": [
    {"over": ["maya"], "amount": 45, "text": "45 pages"},
    {"over": ["more"], "text": "how many more?"}
  ]
}