Transposing means changing the key of a piece of music. This can apply to a scale, a riff, a short melody, or an entire piece of music. The ability to transpose is an important skill for all musicians to develop. The easiest way to transpose is to write the scale degrees under the original melody and then work out which notes correspond to those scale degrees in the key you want to transpose to.
The following short melody in the key of C is also shown transposed to two other keys. On a separate sheet of paper, copy the following three exercises. Then work out the transposed keys and fill in the scale degrees below each note. Play through them and notice that while the melody sounds the same, the overall pitch may be higher or lower. Transpose this melody to all the remaining major keys found in the key cycle. You should also try this same technique with other tunes you know, until you can transpose easily and quickly.