XSL stylesheet Using variables to calculate - xslt

Question

XML file:
<formattedEgGesamt>270.​94</formattedEgGesamt>
<formattedEgGesperrt>50.00</formattedEgGesperrt>
<formattedHgGesamt>78.18</formattedHgGesamt>
<formattedHgGesperrt>4.00</formattedHgGesperrt>
In my XSL file, I declare 4 variables:
<xsl:variable name="HGGesamt">
<xsl:value-of select="format-number(/Basis/PersonenkontoDTO/formattedHgGesamt,'#.00')"/>
</xsl:variable>
<xsl:variable name="HGGesperrt">
<xsl:value-of select="format-number(/Basis/PersonenkontoDTO/formattedHgGesperrt,'#.00')"/>
</xsl:variable>
<xsl:variable name="EGGesamt">
<xsl:value-of select="format-number(/Basis/PersonenkontoDTO/formattedEgGesamt,'#.00')"/>
</xsl:variable>
<xsl:variable name="EGGesperrt">
<xsl:value-of select="format-number(/Basis/PersonenkontoDTO/formattedEgGesperrt,'#.00')"/>
</xsl:variable>
These variables are used to calculate the difference between formattedHgGesamt and formattedHgGesperrt, and formattedEgGesamt and formattedEgGesperrt.
The result should be printed.
Here's the code used to print the 2 results:
<fo:table-cell padding="3pt" display-align="center" border-style="solid" border-width="1pt" border-color="white">
<fo:block font-family="Courier" text-align="right" font-weight="bold">
<xsl:value-of select="format-number(exsl:node-set($HGGesamt)-exsl:node-set($HGGesperrt),'#.00')"/> €
</fo:block>
</fo:table-cell>
<fo:table-cell padding="3pt" display-align="center" border-style="solid" border-width="1pt" border-color="white">
<fo:block font-family="Courier" text-align="right" font-weight="bold">
<xsl:value-of select="format-number(exsl:node-set($EGGesamt)-exsl:node-set($EGGesperrt),'#.00')"/> €
</fo:block>
</fo:table-cell>
The result of the first lines of code, concerning HGGesamt and HGGesperrt are printed and the result is right.
For the EGGesamt-EGGesperrt, it only prints "NaN"
Does anybody have an idea, why?

Answer 1

There seems to be a non-digit character with Unicode 8203 (U+200B, zero width space) in the data of <formattedEgGesamt>270.​94</formattedEgGesamt>,. after the decimal point. So that way the number computations result in NaN.

Answer 2

As #martin-honnen said.
There's also easier ways to get the numbers that you want, e.g.
<xsl:variable name="HGGesamt" select="/Basis/PersonenkontoDTO/formattedHgGesamt"/>
<xsl:variable name="HGGesperrt" select="/Basis/PersonenkontoDTO/formattedHgGesperrt"/>
<xsl:variable name="EGGesamt" select="/Basis/PersonenkontoDTO/formattedEgGesamt"/>
<xsl:variable name="EGGesperrt" select="/Basis/PersonenkontoDTO/formattedEgGesperrt"/>
and:
<xsl:value-of select="format-number($HGGesamt - $HGGesperrt,'#.00')"/> €
...
<xsl:value-of select="format-number($EGGesamt - $EGGesperrt,'#.00')"/> €