QUOTE(Andy-piano-flute @ Oct 28 2007, 09:52 PM)

I play the flute so can read lots of leger lines easily enough - but find lots of treble leger lines slightly more difficult to identify in piano music than flute music.
I find that, too. I also find legers above the stave far less scary than legers below

and leger lines on bass or alto clef much less automatic than on treble (my reading of treble is much more fluent than of bass or alto even though I'm OK at reading those).
I quite often read from the bass clef and transpose whilst playing the flute and don't have a problem - it's automatic to transpose to an appropriate octave and I don't find it hard to read bass clef and play on a treble clef instrument... I quite often swap between lines between verses to vary the harmony, or swap mid verse if there's a particularly juicy bit of harmony I like playing... a C is a C is a C, and what clef I am reading it from/where I am transposing to are not something I have to think about... BUT - I am I suspect more fluent in bass than your daughter is in treble just yet, and I have been playing the flute a long time so don't have to worry about thinking about fingerings once I know what note I am aiming for, it's pretty automatic and so it's far, far easier than if it were an instrument I had not been playing for that long. SO I think it's pretty tough thing she's being asked to do.
Even then, though 99% of the time I don't have to think about it and can play any of the lines competently wherever on the flute I decide to play 'em, I'll STILL have moments where I have total bass-clef blindness and have a mare/play something totally unrelated to what I am reading! & I have no idea at all what it would be like to do try & it from alto clef which is probably a fairer representation of what treble is like for your daughter... I think I could do it but it would require brain gymnastics that would be pretty taxing

I also think that at least to some extent transposing at the octave is easier on an instrument like the flute, which has obvious similarities between the octaves (even more so, on, say, piano - where position on the keyboard is the difference), than on a string instrument where playing an octave higher or lower generally involves a different fingering on a different string

I've done that on violin, I think, and certainly done it on viola, but it involves more brainpower, & is not something I would do _nearly_ as confidently or as easily as on flute. Probably also because I'm not as good as strings as at flute, yes, but even so, I've been playing the violin for a very long time and it would still phase me more to try it on that than on the flute, and I think it's just less obviously logical on strings. And particularly cello where even just to play sharps and flats can involve a different finger (as opposed to just a different finger position) or even a change of position. Eeek.
One thing I DO find helpful, though I don't think about it consciously, is playing by interval rather than by note - ie once I am in the right place on the instrument, then I don't tend to be going "A, B, G, D" but more likely "third up, 2nd up, 4th down" and trusting in my fingers to stay on key. Whether this will help or not probably depends on how fluently she reads intervals, though, I guess.
Um. Sorry, I've waffled a lot, don't know how much is useful. Oops

hopefully a little, even amongst all the randomness.
On the whole... I think it's a useful skill, & possibly a good one to try... but I think it's an awfully tough task to be asked of your daughter at this stage in her cello playing

& I think it's rather unreasonable for her teacher to ask this of her when all the other children are playing from a clef they are used to and (one assumes) not having to transpose. The teacher should SURELY know that this is tough for a child at her stage of playing, and even if she "has" to set these tasks for some reason, she should certainly take into account that your daughter is performing a much more complex task than others playing treble-able instruments who are, presumably, just basically doing some sight-reading.
I'm inclined to agree with cellocase - do both... as, as long as it doesn't totally throw her, it's a great skill to have/practise, BUT her teacher really must be made aware (if she isn't already) of what she's asking your daughter to do & how difficult it is.