[PD] playing sample backwards using line object?

hi all

I know its probably stupid thing but I need to play a sample backwards using the line object to read from a table and I dont understand what i am doing wrong.

To play forward i pass, for example, this message to the line~ object 1, 4.41e+008 1e+007 and its fine, the whole sound plays

i pass this message 44100, 0 1000

and it plays backwards 1 sec but, whats the realation between this and the previous message, i mean i supose i need to pass something like this 4.41e+008, 1 1e+007

to play 2 secs backwards on normal frequency. But it doesnt sound at all. THen i realised that if i do this : 1, 44100 1000 and 44100, 1 1000 it works fine both backwards and forward.

And so my problem is that i dont understand what this mean: 1e+007

could anyone explain little bit the meaning of the numbers like 1e+007 or 4.41e+008 to the ones of us that dont have a good understanding of maths?

thank you very much!