Creating a piped text / embedded data formula

Hello,
I wanted to create a formula in order to later use the data + show the results at the end of the survey for my participants, but for some reason I can't get it right.
I need to subtract one factor from the other and my questionnaire is in Hebrew so I created a few versions of the formula just to make sure what is the right combination.
Those are my factors:
co - ${gr://SC_cLPINbSIeRMxeNE/WeightedMean}
mrat - ${gr://SC_8uoMmrrJSO1RLls/WeightedMean}
I would like to substract mrat from co (co - mrat), so those are the versions I created by neither is working.
$e{ gr://SC_cLPINbSIeRMxeNE/WeightedMean - gr://SC_8uoMmrrJSO1RLls/WeightedMean }
{ gr://SC_cLPINbSIeRMxeNE/WeightedMean - gr://SC_8uoMmrrJSO1RLls/WeightedMean }#$
$e{ gr://SC_cLPINbSIeRMxeNE/WeightedMean - gr://SC_8uoMmrrJSO1RLls/WeightedMean }
{ gr://SC_cLPINbSIeRMxeNE/WeightedMean - gr://SC_8uoMmrrJSO1RLls/WeightedMean​​​​​​​ }#$
${gr://SC_8uoMmrrJSO1RLls/WeightedMean}
${gr://SC_cLPINbSIeRMxeNE/WeightedMean}

Does anyone know how to fix it?
Have a good weekend,

Daniel