You should always have error handling code when dealing with OS variable reading/creating. Here are routines for both directions, with error handling.
OS float to Axe variable:
If GetCalc("varA") .var is the u token found at 2nd+7
float{}→A .float{ is the fPart( token
Else
.Not found
End
Axe variable to OS float:
A→float{GetCalc("varA",7)}
!If and 0
.Not enough RAM
End