{
  "problem": "Solve for $r$ : $18 = 30 + r$",
  "hints": [
    "Subtract",
    "$30$",
    "from both sides:",
    "$ \\begin{eqnarray} \\\\ \\hphantom{18 {- 30}} &\\hphantom{=}& \\hphantom{r} \\\\ 18 &=& 30 + r \\\\ \\\\ {-30} && {-30} \\\\ \\end{eqnarray} $",
    "$ \\begin{eqnarray} \\\\ 18 {- 30} &=& r \\\\ \\end{eqnarray} $",
    "Simplify. $ r = -12$"
  ]
}
{'source': 'AMPS', 'file': 'amps/khan/309/1607907416.json'}