Simplify the following text for a Grade 15 native English-speaking person.
Original: Later in the Tang dynasty , Cao Rou ( æ æ '' ) and others simplified the notation , using only the important elements of the characters ( like string number , plucking technique , hui number and which finger to stop the string ) and combined them into one character notation .
Simplified: Later in the Tang dynasty , Cao Rou and others simplified the notation , using only the important elements of the characters ( like string number , plucking technique , hui number and which finger to stop the string ) and combined them into one character notation .