First two are
Rentenmark issues. The Rentenbank was established to help stabilize the German economy after the hyperinflation of the 1920's. For some reason, the Nazis allowed them to continue to issue low-denomination banknotes. These are some of those later notes (Pick # 173 and #174), dated 1937 but also issued up to and during WWII.
The next one is older. It's dated 1910, listed as Pick #40. It comes in two varieties, "with watermark" and "without watermark". The watermarked version is slightly scarcer. Hold the note up to the light; if you can see the words"20 MARK", it's the watermarked one.
