When you add 1/8 and 1/8, you are essentially adding two equal parts of an eighth. Since both fractions have the same denominator, you can simply add the numerators together.
1/8 + 1/8 = (1 + 1)/8 = 2/8
Now, 2/8 can be simplified by dividing both the numerator and the denominator by their greatest common divisor, which is 2.
2/8 ÷ 2/2 = 1/4
So, 1/8 plus 1/8 equals 1/4.