In one box there are 80 pieces of nails, and in the other half is less. What is a quarter of half of all nails equal to?

Let’s calculate how many nails are in the second box, if we know, according to the conditions from this problem, that there are twice as many in the first:
80: 2 = 40.
Let’s calculate how many nails are in the first and second boxes:
40 + 80 = 120.
Let’s calculate what is equal to 1/4 of 1/2:
1/2 * 1/4 = 1/8.
Let’s calculate how many nails are equal to 1/8 of their total number:
120 * 1/8 = 15.
Answer: One fourth of half of the nails that are in two boxes is 15 nails.