=t207-s207

or with minor checking...
=if(count(s207:t207)<2,"not enough numbers!",t207-s207)
or make the cell look empty
=if(count(s207:t207)<2,"",t207-s207)

Doug wrote:

What function would I use in cell U207 to take cell S207 multiplied by -1 and
add it to cell T207
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Thank you!

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Dave Peterson