rank question

[Tatsuro MATSUOKA]

Hello

Perhaps I have mislead

>> A=[
1,2,3,4,5,6,7
7,6,5,4,3,2,1
9,10,11,12,13,14,16
6,4,2,0,-2,-4,6
10,12,14,16,18,20,22
]
A =

    1    2    3    4    5    6    7
    7    6    5    4    3    2    1
    9   10   11   12   13   14   16
    6    4    2    0   -2   -4    6
   10   12   14   16   18   20   22

>> rank(A)
ans =  3
The same results  are obtained on Scilab and Maxima.

However, row basic deformations of A give to 

    1    2    3    4    5    6    7
    0   -8  -16  -24  -32  -40  -48
    0   -8  -16  -24  -32  -40  -48
    0   -8  -16  -24  -32  -40  -48
    0   -8  -16  -24  -32  -40  -48

    1    2    3    4    5    6    7
    0    1    2    3    4    5    6
    0    0    0    0    0    0    0
    0    0    0    0    0    0    0
    0    0    0    0    0    0    0

Is not the rank of A two (2)?
Am I misled ?

Tatsuro