1/2
5/8-1/8=4/8, we know this because when subtracting fractions with the same denominator, you keep the denominators the same and subtract the numerators. 5-1=4. this gives you 4/8. now, we know 4 is half of 8, so this is equal to 1/2, but we also can divide both 4 and 8 by 4, giving us 1/2.