The combined area is 80 acres, not 120. The north half of the northeast quarter contains 640 x 1/4 x 1/2 = 80 acres. The northeast quarter of that northeast quarter contains 640 x 1/4 x 1/4 = 40 acres, but it is already inside the first parcel.

For total distinct area, count overlapping ground once: 80 + 40 - 40 = 80 acres. A simple sketch shows why addition alone gives the wrong result. Both descriptions must refer to the same section for this example to work.

Our discussion about AND in legal descriptions covers separate pieces. The acreage worksheet adds this overlap check. The numbers are classroom assumptions; use appropriate survey and title information for an actual property.