Using a builders level A Grade for a footing being set, the bottom of the footing will be at an elevation of 94.00. A backsite to the benchmark (elevation 100) has a rod reading of 4.70. What should the rod reading at the bottom of the footing be if the Grade is correct? (note the footing is 6″ thick)

Using a builders level A Grade for a footing being set, the bottom of the footing will be at an elevation of 94.00. A backsite to the benchmark (elevation 100) has a rod reading of 4.70. What should the rod reading at the bottom of the footing be if the Grade is correct? (note the footing is 6″ thick)