diff --git a/format-master.xml b/format-master.xml
index 5d7abbf..0f3125c 100755
--- a/format-master.xml
+++ b/format-master.xml
@@ -140,12 +140,18 @@
 
 	<!-- I think the pi symbol is only available in LaTeX in math mode, but if we're already in math mode, the extra $ signs will mess things up... -->
 	<!-- Can we use XSLT modes to deal with this? -->
-	<template name="pi" match="pi">
-		<!-- <latex>$\pi$</latex> -->
+	<!-- Looks like a "yes": -->
+	<template name="pi-math" match="pi" mode="math">
 		<latex>\pi</latex>
 		<html><xsl:text disable-output-escaping="yes">&amp;#960;</xsl:text></html>
 	</template>
 
+	<!-- Not in math mode: -->
+	<template name="pi-normal" match="pi">
+		<latex>$\pi$</latex>
+		<html><xsl:text disable-output-escaping="yes">&amp;#960;</xsl:text></html>
+	</template>
+
 	<template name="LaTeX" match="LaTeX">
 		<latex>{\LaTeX}</latex>
 		<html>L<SUP>A</SUP>T<SUB>E</SUB>X</html>
@@ -1272,12 +1278,12 @@
 		<math> on its own is assumed to be displayed in its own paragraph.
 	-->
 	<template name="math-inline" match="paragraph//math|para//math|p//math">
-		<latex>\(<xsl:apply-templates/>\)</latex>
+		<latex>\(<xsl:apply-templates mode="math"/>\)</latex>
 		<html><xsl:apply-templates/></html>
 	</template>
 	
 	<template name="math-display" match="math">
-		<latex>\[<xsl:apply-templates/>\]</latex>
+		<latex>\[<xsl:apply-templates mode="math"/>\]</latex>
 		<html><P ALIGN="center"><xsl:apply-templates/></P></html>
 	</template>
 
@@ -1288,7 +1294,7 @@
 		<latex>
 			<xsl:text>\begin{eqnarray*}
 </xsl:text>
-			<xsl:apply-templates/>
+			<xsl:apply-templates mode="math"/>
 			<xsl:text>
 \end{eqnarray*}</xsl:text>
 		</latex>
@@ -1298,9 +1304,7 @@
 	</template>
 
 
-	<!-- No, don't put in an alias, because you'd also need one for eqnarray//row.
-	<xsl:template match="eqnarray"><xsl:call-template name="equation-array"/></xsl:template> -->
-	<!-- Hmm, LaTeX uses & as separators: how do we know if there's another cell coming?  Ah, but the LaTeX eqnarray can have no more than three columns, so there's no need to generalise. -->
+	<!-- Hmm, LaTeX uses "&" as separators: how do we know if there's another cell coming?  Ah, but the LaTeX eqnarray can have no more than three columns, so there's no need to generalise. -->
 	<template match="equation-array/row">
 		<latex>
 			<xsl:apply-templates select="left"/><xsl:text disable-output-escaping="yes">	&amp;	</xsl:text><xsl:apply-templates select="middle"/><xsl:text disable-output-escaping="yes">	&amp;	</xsl:text><xsl:apply-templates select="right"/><xsl:text>	\\
@@ -1312,7 +1316,7 @@
 	</template>
 	
 
-	<!-- Digit grouping separator character for large numbers. -->
+	<!-- Digit grouping separator character for large numbers.  SI conventions say this should be a space (but we could make it a comma if desired). -->
 	<template name="digit-group-separator" match="digit-group-separator">
 		<common>
 			<xsl:call-template name="non-breaking-space"/>
@@ -1353,6 +1357,13 @@
 	<template name="equals-operator" match="math//equals">
 		<common> = </common>
 	</template>
+
+	<template name="approximately-equals-operator" match="approximately-equals-operator">
+		<latex>{\approx}</latex>
+		<html><xsl:text disable-output-escaping="yes">&#8776;</xsl:text></html>
+	</template>
+	<alias source="approximately-equals" target="approximately-equals-operator"/>
+	<alias source="approximately-equal-to" target="approximately-equals-operator"/>
 	
 	<!--
 		The equivalent of LaTeX's "log-like functions".
