[Jprogramming] working with content of boxes

[Rudolf Sykora]

Dear list,


say I have a variable
   ee
+----------------------+-----------------------+
|+---+---+----------+-+|+---+---+----------+--+|
||129|144|51582.8125|7|||128|143|51545.3125|22||
|+---+---+----------+-+|+---+---+----------+--+|
+----------------------+-----------------------+

how can I
1) join the first two boxes on level 0 into a single box, ie. get

+----------------------+-----------------------+
|+---+---+----------+-+|+---+---+----------+--+|
||129 144|51582.8125|7|||128 143|51545.3125|22||
|+---+---+----------+-+|+---+---+----------+--+|
+----------------------+-----------------------+

2) do an arithmetic operation on the 'position of big numbers of about
51000', ie. the 3rd box on level 0 of the original variable; eg. I want
to subtract 50000 from them...

?

Thank you for comments!
Rudolf Sykora