Totals run sideways as often as they run down.
The quarterly sheet has one row per product and one column per month. In E2:E4 give each product's quarter total, and in E5 the grand total of every cell in the block.
Solve it on your own to keep the bonus. Each hint gets one step closer to the formula.
The same formula in the other shapes it takes at work.
A total is the first thing anyone asks a spreadsheet for.
Add two blocks of figures without dragging the subtotal between them into the total.
One formula, filled down, that shows the balance after every line.
Totals run sideways as often as they run down.
This is the grid you start with. Cell references in the task — B6, C2 — point at the row numbers and column letters below.
| A | B | C | D | E | |
|---|---|---|---|---|---|
| 1 | Product | Jan | Feb | Mar | Quarter |
| 2 | Notebooks | 420 | 385 | 510 | |
| 3 | Pens | 1310 | 1180 | 1265 | |
| 4 | Folders | 240 | 275 | 230 | |
| 5 | All products |
Summing the block B2:D4 rather than the three row totals means the grand total does not depend on E2:E4 being right. If someone overtypes one of them with a number, the two totals stop agreeing, which is exactly how you would notice.