Hi,
Can´t you solve it on your own?
take a piece of paper and a pencil.
Then decide if you want signed or unsigned 8 bit representation.
Decide the highest absolute value.
Write this value 8 times among each other
calculate the sum.
The decide which bith width you need for this number.
********
mathematically:
* input_bit_width ( 8 bits)
* add_count (8)
output_bit_width = input_bit_width + log(add_count) / log(2)
Try both and see if both results match.
Decide why they don´t match exactly.
Klaus