EASY (IER) KANJI - JLPT 4 KYUU

This one also has several more readings, but shita is the most useful for now

1) ka, 2) ge, 3) shita - bottom, under, down

靴下 kutsu shita - socks [lit. shoes under]
地下 chi ka - underground, basement
年下 toshi shita - junior, younger, young