Soulver is basically a notepad application that lets you write out what calculations you’re doing and then does the computation next to it. I like it because my fundamental failing in maths is keeping track of what I’ve done, what I’m doing now and where I go from there. Soulver lets you type out a document, with variables and dependent answers if you want, that neatly sets out your working. It means that you don’t feed numbers into a calculator and, on going back, wonder “where did that 50p come from?”. It’s also great used as a more regular text editor to take notes where numbers are involved.
For example, the above is a question I worked out in a tax tutorial (by the way, if you rely on my figures here to calculate the dividend in your own company you’re literally crazy). I typed out the numbers again but I could also have dragged and dropped from the right hand side into the text window on the left. That has the advantage of putting in pointers which can change as the calculations they rely on change, just like a spreadsheet formula.
The developer makes no claims for Soulver’s accuracy, reliability or correctness. You should always check the accuracy of the results, and not rely on them being correct.
Soulver should not be used in cases where errors or inaccuracies in a result would lead to death, personal injury, financial and economic losses, losses, damage to property, or any other form of damage.
I suspect that whoever wrote that had the Mars Climate Orbiter in mind when doing so. The MCO crashed because of a communication error between multiple teams — one team did their work in metric units, another team used imperial ones. The resulting disparity meant that the spacecraft crashed. Similarly, my own example of using Soulver to calculate company tax creates opportunities for some crazy liabilities. Soulver’s killer feature here, every calculation is neatly written down and stored line by line, means that there is a paper trial built up for exactly where the error happened; that’s not the same as blaming Casio when your tax return gets audited.
I think this makes a dramatic contrast to the “use at your own risk” EULA found by Michael @ Law Actually.