Easy:

There are more Chinese men in the world than Japanese men.

Hard:

Normal - i wouldn’t be very happy if I had all 10 of my fingers on one hand.

Super Hard:

Step 1: Fill up the 3L, and pour it into the 5L.

Step 2: Fill the 3L again. Pour 2L into the 5L container so that 1L remains in the 3L container.

Step 3: Empty the 5L. Pour the 1L of water from the 3L container into the 5L container.

Step 4: Fill the 3L container again. Pour it into the 5L container that already has 1L of water in it.