Simplify the following text for a Grade 9 native English-speaking person.
Original: Gabriela played at Barack Obama 's presidential inauguration on 20 January 2009 together with the cellist Yo-Yo Ma , the violinist Itzhak Perlman , and clarinetist Anthony McGill . Together they performed `` Air and Simple Gifts , '' a new arrangement by John Williams based on the Shaker hymn Simple Gifts .
Simplified: Montero performed John Williams ' `` Air and Simple Gifts '' with Itzhak Perlman , Yo-Yo Ma , and Anthony McGill at the inauguration of U.S. president Barack Obama on January 20 , 2009 .