The first measure has 2 quarter notes, and each one gets one count. You can count them as "one two." The second measure has 4 eighth notes, written as pairs with their tails connected.
The first place to start with subdivisions of the beat is learning to feel the eighth note subdivision. Most music is in 4/4 time (see time signatures). That means 4 beats per bar/measure and each beat equals 1 quarter note. If we divide each of those quarter note beats in half, we get 8 eighth notes.
There are 1000 mililiters in one liter. Since there are two liters, it means there´s 2000 mililiters. He drink half of it, so 1000 mililiters are left.
