Honestly I can see an argument for 7 shelves or for 8 shelves.
When you do the calculation;
You get 7.15 shelves. Clearly you cannot have .15 of a shelf so the logician in me wants to say you need 8 shelves!
But if the assignment is aimed estimation skills, (Which is what I assume is being implied by the title of the assignment), then the easier calculation of
is probably what the teacher was hoping for.
You might have been accidentally been calculating
. Remember division is NOT communitive! i.e.
.
From the image;
The first step was to see that 59 can not go into 4..resulting in the zero above the 4, multiplying 0 by 59 and subtracting 0 from 4.
The second step begins by bringing down the 2, seeing that 59 can not go into 42..resulting in the zero above the 2, multiplying 0 by 59 and subtracting 0 from 42.
The third step begins by bringing down the 2, seeing that 59 can go into 422 7 times (I tested this on the right by a short multiplication problem)..resulting in the 7 above the 2, multiplying 7 by 59 and subtracting 413 from 42.
This process continues....