Fraction': [
          {
            title: 'Fraction',
            pic: 'fraction-1.gif',
            latex: `-\\frac{2}{x+1}\\ne-\\frac{x+1}{2}`,
          },
          {
            title: 'Fractions of fraction',
            pic: 'fraction-2.gif',
            latex: `-\\frac{-\\frac{1}{2}}{-\\frac{3}{4}}`,
          },
          {
            title: 'Tall Fraction',
            latex: `\\sqrt{
\\frac{x}{
  \\frac{
    \\frac{\\frac{3}{4}}
    {5}
  }
  {2}
  }
}`,
          },
          {
            ti