MATLAB: What is the difference between manually generated data and loaded data or random data

dataloadrandom number generator

If we have a matrix stated as below a =
   -0.3252    0.1231   -0.1236
    0.3690   -0.3574    0.3214
    0.8524   -1.2658   -1.3698
then we would have 
EDU>> a(2,1)==0.3690
ans =
     1
But if we have a matrix which contains random numbers generated by MATLAB such as b=rand(3,3)
b =
    0.2293    0.1496    0.0159
    0.1822    0.2027    0.9575
    0.1664    0.9550    0.0257
then very suprisingly we would have 
b(2,1)==0.1822
ans =
     0
I came up to this problem while using the load data.mat command. In case I load the data it would face the same problem as randomly generated data.Can you please proide me an answer for this problem. Thank you
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