Hi el96jay,
In Word, add a numeric picture switch to the mergefield. To do this:
.. select the field;
.. press Ctrl-F9 to reveal the field coding. It should look something like {MERGEFIELD MyData};
.. edit the field so that you get {MERGEFIELD MyData \# $,0.00} (or whatever other numeric format you prefer - see below);
.. position the cursor anywhere in this field and press F9 to update it;
.. run your mailmerge.
Note: The '\# 0' in the field is referred to as a numeric picture switch. Other possibilities include:
.. \# 0 for rounded whole numbers
.. \# ,0 for rounded whole numbers with a thousands separator
.. \# ,0.00 for numbers accurate to two decimal places, with a thousands separator
.. \# $,0 for rounded whole dollars with a thousands separator
.. \# $,0.00;($,0.00);- for currency, with brackets around negative numbers and a hyphen for 0 values