Press the Add to Total button repeatedly to add to the sub-totals. You can scroll back and forth through the sub-total history to double check your numbers if need be.
Click here to learn more about the “++” Calculator
The ++ Calculator mimics a feature from calculators we had in primary school in the 1980s and 1990s and it seems to have disappeared from modern calculators.
You would type in a number, press the + button twice, then press the = button over and over. Each time you pressed = it would add the original number to the running total.
This feature has disappeared from modern calculators and the calculators on our phones, but it’s useful if you are building concrete stairs because the quickest, easiest and most accurate way to mark out to build stairs is to mark each riser location along the throat of the stairs.