Kepler & K2 provide long-baseline, high-precision photometry for exoplanet and astrophysics research.
The basic and most common additional rule for Doubles play is that where a Double exists at the end of any train, the Double must then be 'satisfied' (laid against) in the next turn, even if the Double is on another player's train that is not marked.
In order to teach play skills, you should model a happy and excited affect. The child is observing not just the play skill, but your face, voice tone, and mannerisms. Make sound effects, clap, laugh, smile, speak in funny voices, yell, and cheer as you play with the child.