Zhang Long has a ball, Zhao Hu has a ball, Wang Fang has a ball and Ma Yuan has a ball.

a+b+c+d=45

Zhang Long conceded two goals.

(a-2)

Zhao Hu added two goals (b+2),

Wang Fang's ball doubled (2c),

The ball in the horse circle is reduced by half (d/2)

(a—2)=(b+2)

(b+2)=(2c)

(2c)

=(d/2)

Four equations

Four unknowns, it is possible to find four values of abcd.