def fmttime(tin):
    """Return LaTeX expression with time in scientific notation.

    Args:
        tin (float): the time.
    Returns:
        str: the LaTeX expression.
    """
    aaa, bbb = '{:.2e}'.format(tin).split('e')
    bbb = int(bbb)
    return r'$t={} \times 10^{{{}}}$'.format(aaa, bbb)