I want to do some calculations with the values i receive from MQTT.
The "convert functions" converts the string, coming from the MQTT, to a number.
msg.payload = Number(msg.payload);
What i want to do is : subtract the number that is coming from MQTT "rem/rechts" with the number that is comming from MQTT "rem/links" this result must be devided by MQTT "rem/links" and multiplied by 100 => the result is the difference between MQTT "rem/rechts" and "rem/links" in %.
thanks for your help