1/8 of the book because
5/8 is what she read on the second day so
So you will have to do 1/4 to make 1/4 be in the /8 so then that would equal 2/8
5/8 plus 2/8 is 7/8 and 8/8 minus 7/8 is 1/8
So 1/8 is what she read on the third day
If you need it in decimal for it would be 0.125
Hope I helped
