2 1 10 Williams, Richard Primary Author mixed material 9781844168897 Nottingham: Black Library 2011 https%3A%2F%2Fsipadu.um.ac.id%2Fadmin%2Fpengolahan_buku%2Fimages%2Fupdbuku%2F39614.jpg arithmetic and algebra / Richard Williams Williams, Richard Primary Author mixed material 0673154823 Glenview, Illinois : Scott, Foresman and Company 1984 https%3A%2F%2Fsipadu.um.ac.id%2Fadmin%2Fpengolahan_buku%2Fimages%2Fupdbuku%2F12503.jpg