If \(a\), \(b\), \(c\), and \(d\) are four different digits from \(1\) to \(9 \), inclusive, then what's the largest possible value for the decimal \(a.b+c.d\)?
If \(a\), \(b\), \(c\), and \(d\) are replaced by four distinct digits from \(1\) to \(9 \), inclusive, then what's the largest possible value of the difference \(a.b-c.d\)?
If \(a\), \(b\), \(c\), and \(d\) are replaced by four different digits from \(1\) to \(9 \), inclusive, then what's the largest possible value for \(a.bc+0.d\) ?
