I attach spreadsheets in OneNote quite often. Most are a calculation or a running list with totals. While I consider this functionality a great asset to OneNote, I think most of my embedded sheets could live in the native OneNote table more elegantly if basic spreadsheet type calculations could be built in.

For instance summing a column, or allowing several cells to be used mathematically to compute a result. This sort of basic math interpretation is already part of OneNote since I can type an expression followed by an "=" and it automatically computes. Building such into a table is not a far reach from this.