%mathpiper,def="IsRationalOrNumber"

10 # IsRationalOrNumber(x_IsNumber) <-- True;
10 # IsRationalOrNumber(x_IsNumber / y_IsNumber) <-- True;
10 # IsRationalOrNumber(-(x_IsNumber / y_IsNumber)) <-- True;
60000 # IsRationalOrNumber(_x) <-- False;

%/mathpiper