title: Plot text containing "approximately equal to" in R
body: <p>I am familiar with using <code>expression()</code> and <code>bquote()</code> when plotting special Tex like markup in textual base graphics in R.  But how to do "approximately equal to" without having the parser throw an error.  I am referring to <code>?plotmath</code> when determining the markup.</p>
  
  <pre><code>plot(c(1,100), c(1,100), type="n", axes=FALSE, xlab="", ylab="")
  
  # This works
  text(50, 80, expression(paste("The area is 24 ", km^2)))
  
  # This doesn't
  text(50, 50, expression(paste("Reginald is ", %~~% , "14 years old")))
  </code></pre>