Burgmüller Op. 100, no. 4 A Little Party
You’d expect a collection of etudes to feature an excercise in thirds, and Op. 100 is no exception. Here we have ascending and descending thirds, in both legato and staccato. The articulation is easily managed with the proper fingering, since the position changes line up with the legato phrasing. Also note the legato sixths: the thumb (on the bottom notes) isn’t going to be much help here, so be sure to use your 3, 4, and 5 for the upper half of the intervals to keep the melody smooth.