= 2/3 times (1-5/8)

=2/3X3/8

= 1/4

(2) Solution: 4/13x2/7+4/7x11/3.

= 1/ 13 x2/7x(4+2x 1 1)

=2/( 13x7)x26

=4/7

Key points: be skilled in extracting common factors!