[WP34s] Unexpected results in fraction mode

[Dieter]

I just did a few calculations in fraction mode and got some results I would not have expected. Note: DECM is "H.d" on the 34s keyboard.

Code:

  keys           display
  [.] 1 [.] 6
     [ENTER]     1/6
     [1/x]       5 1/1
     [DECM]      6    // actually 5,999999...9

  [.] 3 [.] 1    // enter 3 and set fraction mode again
     [sqrt]      1 5822/7953
     [x²]        2 1/1
     [DECM]      3    // actually 2,999999...9

Another example: 7/120 – 1/17 = –1/2040

Code:

  keys           display
  [.] 7 [.] 120
  [ENTER]        7/120
  17 [1/x]       1/17
  [-]           -1/2040

  [1/x]         -2039 1/1
  [DECM]        -2040

Hm. The 34s obviously does not round up (standard RM 0 was set), resp. it does not simplify 5 1/1 to a plain 6 or 2039 1/1 to 2040. Unlike my trusted 35s:

Code:

  keys           display
  [FDISP]
  6 [1/x]        0 1/6
    [1/x]        6
  [FDISP]        5,99999999999

  [FDISP]
  [.] 7 [.] 120
  [ENTER]        0 7/120
  17 [1/x]       0 1/17
  [-]           -0 1/2040

  [1/x]         -2040
  [FDISP]       -2039,99999971

Is this the intended way of displaying near-integers or is it a... hm... "special feature" of the 34s? Why does it do this "1/1" thing?

There is another thing I would not have expected, and this time I would consider it a bug. Do the 7/120 – 1/17 example again and round the result:

Code:

  keys           display
  [.] 7 [.] 120
  [ENTER]        7/120
  17 [1/x]       1/17
  [-]           -1/2040

  [1/x]         -2039 1/1    // result is -2039 1/1 or -2040

  [ROUND]        2040 0/1    // result has lost its sign, now it is positive!
  [DECM]         2040

I think this should get corrected.

Dieter