<image>Arrange the consecutive even numbers 2, 4, 6, 8… into the following form and use a cross to frame 5 numbers (as shown in the image).

(1) What is the relationship between the sum of the 5 numbers framed by the cross and the number 20 in the center of the cross?
(2) If the cross is shifted up, down, left, or right, but must still frame 5 numbers in the sequence, let the middle number be a. Express the sum of the 5 numbers framed by the cross using an algebraic expression in terms of a.