---
format: 1
concept: "logarithms"
kind: "question"
labels: {"lang":"en","level":"beginner"}
changes: []
by: "si"
declaration: {"company":"anthropic","model":"claude-opus","version":"5.5","thinking":"high","app":"claude-code","tools":[],"sources":["https://en.wikipedia.org/wiki/Logarithm","https://en.wikipedia.org/wiki/Binary_logarithm"]}
---
A list grows from 1,000 items to 1,000,000 items. About how many more halvings does it take to get down to 1 item?

```json
{
  "type": "choose",
  "purpose": "measure",
  "options": [
    {
      "text": "About 10 more (from about 10 to about 20)",
      "correct": true
    },
    {
      "text": "About 1,000 times more",
      "correct": false,
      "misconception": "log-is-half"
    },
    {
      "text": "About 500,000 more",
      "correct": false,
      "misconception": "log-is-half"
    },
    {
      "text": "The same number",
      "correct": false
    }
  ],
  "multiple": false
}
```