The meaning of the question is ambiguous.
Five eights is 5*8 = 40
Two eighths (?) is 2/8 = 1/4 = 0.25
So the sum would be 40.25
Alternatively five eights plus two eights = seven eights = 7*8 = 56
Five eights plus two thirds minus one fourth is equal to 1.04
11 and 31 over 40
5 37/40
Five and seven eighths
3 3/8
51/8= 6 3/8
3/8
eleven and twenty three over twenty four.
it is 6 eights or 3/4
25/40 + 16/40 = 41/40 = 1 and 1/40
Five sixteenths.
1.25