If you want all rational numbers to look like this, then there isn't a convenient way to make that happen in Sage. I'm currently working on a framework to allow one to do this, but it's not ready yet. I will update this post when there is a ticket in question

However, if you just want a function that will return a string in the right form, you can use something like the following

```
def pprint(rational):
if rational < 0:
return '%s - %s'%(rational.ceil(), rational.ceil() - rational)
elif rational > 0:
return '%s + %s'%(rational.floor(), rational-rational.floor())
else:
return '0'
```