Casio electronic organ can be transposed like this. Every semitone is #C=bD, d, Be, e, f, #F=bG, g, #G=bA, a, bB, b, back to C, and vice versa. With the function of transposition, learning to play notation will be very simple. After adjustment, 1 always corresponds to the key of the central C, regardless of the black keys required by the key signature. Of course, if the symbol shows rising and falling symbols, black keys should be used. To put it simply, start with Do, use a+sign on the right and a-sign on the left to count black and white keys. If Do is increased, it is+1, and so on.