So sorry for the trouble! This is on our list of possible improvements for the future – I can’t say exactly when it’ll be added, but we know it’d be a useful improvement. In the meantime, our apologies for the inconvenience!Rui Silva commented
My sister uses my CCard all the time, and she needs to pay 100% of it all the time. It will be great if she could set as standard with me that she I paid the bill, and she needs to pay me.
We just added a very basic calculator function to our web app, so you can now use basic mathematical operations when entering a cost (addition, subtraction, multiplication, and division). We hope to add similar features to our mobile apps at some point in the future!