what is 40 and a half added by 7 and a half and the same thing 7 and a half

I assume you might mean:

40+ 1/2  +  7 + 1/2  + 7 + 1/2  =

40 + [7 + 7] + [ 1/2 + 1/2 ] + 1/2  =

[40 + 14] + 1 + 1/2 =

[54 + 1] + 1/2  =

55 + 1/2