Spread Sheet

I have a spread sheet I would like to have a sum from another tab from multiple rows and columns. I have a tab named conduit length with dates on row 6 from I6 to IB6 and columns from I7 to I144 through IB7 to IB144.

I would like to be able to type in a date on tab Summary H3 and I3 and have it add all of the footages between the dates I have entered on the Summary tab in H5.

I will attach a screen shot of both tabs.

Thanks