469＋599的简便算法是请选择ABC1r9l(I:|7k;d/C-Y-J7q'j-B+K7`6J+P6Y4f0H8}/G-i0M*K
A.469＋600－17`6J+P6Y4f0H8}/G-i0M*K
B.469＋600＋17`6J+P6Y4f0H8}/G-i0M*K
C.470＋599－17`6J+P6Y4f0H8}/G-i0M*K