Trouble Updating Values in Interactions Panel

Hello!

At times, I struggle with entering the values for my interactions. For example, I had a value set to -40 px that was to be changed to -30. I placed the cursor after the 4 and backspaced. The entire value changed to 0. Ultimately, I got it changed. But then had issues when I went back to change again.

Are there any tricks to entering and updating values for interactions?