[Radio Wrangler]

These are two ways of visualising Kirchoff's.

"Total flowing in must equal total flowing out" is the easiest to visualise, and is easy to use in simple cases when you can see what the currents are and know which is which way.

"Everything adds up to zero", as Julie says is mathematically equivalent, but it comes into its own when you aren't sure of which way any of the currents is flowing. The signs will keep you right without having to know in advance. This is necessary when you're using algebra to analyse a network.

David