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Simplify Maths With Soulver

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Spreadsheets are incredibly powerful tools, as we've seen through our recent series on spreadsheets. They're the original killer app for PCs, the app that that convinced countless businesses that it was time to enter the digital age. Even today, on your computer or phone, a spreadsheet is the easiest way to crunch numbers, and often the most versatile app to make a budget, schedule, or anything else that needs laid out linearly.

The only problem is, spreadsheets are complicated tools that can feel like they take a lifetime to master. Their power comes at a price. That's where simpler spreadsheet-like apps come in. Calca is one of the most powerful, and we've already looked at how you can make Markdown documents with calculations in it. Bu there's a simpler option: Soulver.

Soulver is a simple text-powered calculator app that gives you the power of a spreadsheet with the simplicity of typing out your problems in real words. This tutorial will teach you everything you need to crunch your numbers efficiently with Soulver. Let's dive in.

Numbers Naturally

Rather than requiring you to use specific function commands to perform operations, with Soulver you can use natural English. The simplest way to get a grasp of Soulver is to jump straight in and start using it. In this tutorial I’m going to take your through three sample projects that demonstrate the principals that underly Soulver and will give you the tools to start using Soulver in your workflow.

Before starting, you need to understand Soulver’s concept of Word Operators. When you are talking to someone you rarely say “ten plus ten”, you are far more likely to say “ten and ten”. Soulver leverages this concept; you can use and in place of a plus sign, less instead of a minus, at instead of an asterisks or an x and many others as well.

Soulver also has a smart understanding of units. If you specify something in the price per week and then calculate the price per month, Soulver knows what you want to do.

To start, download a copy of Soulver. It’s a available for Mac, iPhone and iPad. I’m using the Mac version for this tutorial but the features are the same across all three platforms. There is a ten day free trial of the Mac version available from the developer’s website.

Simple Budget

Open a new Soulver document. It is always a good idea to create an introduction for yourself so that, if you find the file in a year or two, you know what it was for.

Soulver automatically pulls the numbers out of anything you write. I don’t want Soulver to take the year as a value to be used so I’m going to write my introduction as a comment. The easiest way to write a comment in Soulver is to preface the line with //. Write something like //Budget for Denmark Trip, 2014.

Soulver budget document 1
The start of my budget Soulver document.

Next it is time to add items to the budget. With Soulver you can use natural language to do this. Just type the expenses in the left column as you would tell them to a friend.

  • The flights are €100
  • Two nights in Copenhagen at €30 a night
  • Transport will be €40
Soulver budget document 2
Adding items to my budget.

In the right column Soulver lists the answer to what you’ve written. If you’ve written a simple statement, like the first line, the answer will be the same as what you wrote. If there is an inherent maths problem, however, Soulver will calculate the result and display that in the answer column instead.

Down the bottom of the document, Soulver keeps a running total. At the moment, the total cost of my trip is €200. If instead you wanted to know the average cost of the different items, click on the Total and select Average. Soulver will tell you that my average expense is €66.67.

Less Simple Budget

I’m still working in the same Soulver document, but now I’m going to start to leverage some of the app’s cooler features.

Add the lines:

  • Museum visits are 300DKK in euro
  • 2 nights in Aalborg at €40 less 10%
Soulver budget document 3
The final budget document.

Soulver regularly pulls exchange rate data so it’s currency conversions are always up to date. For my budget that’s important as I can enter an expense in DKK (Danish Krone) and just add in euro to instantly convert it to a more familiar currency.

You can also use Soulver to work with percentages. Again, Soulver has a smart understanding so you can use real words to calculate discounts, mark ups and interest rates with ease.

Back of the Envelope Calculations

By now you should have a basic understanding of how to use Soulver. For this section, open a new document. Denmark is filled with wind turbines and as I travelled past some I wondered what speed the blade tip moves at. This sort of back of the envelope calculation is where Soulver comes into its own.

Once again, preface the document with a comment. In this case type something along the lines of //Wind Turbine Blade Tip Speed Calculator.

When you are doing any simple physics problems like this, it is good practice to work with variables rather than absolute numbers. This means you can change the variable’s value and the whole equation will update, rather than having to go through and update every number individually. The two important variables are going to be the length of the windmills blades and the time it takes to do a complete revolution.

Enter the lines:

  • BladeLength = 30m
  • RotationTime = 3sec
back of the envelope 1
The opening lines of my back of the envelope calculation.

In Soulver, the equals sign assigns variables. I’ve also added the units after each variable so Soulver can make smart decisions about converting the results. I arrived at these values by timing how long it took a turbine to fully rotate and guessing at the length of the blades. If you want to calculate the speed of different sized, or differently spinning, turbines, you can update the variables at any time which will update the answer.

Tip: You can’t use spaces with variables in Soulver. That’s why I used BladeLength instead of Blade Length.

Next add the line SpinCircumference = BladeLength × 2 pi.

Here you’re setting the SpinCircumfrence variable to be 2 pi times the BladeLength variable. If you remember high school maths, you’ll recall that the circumference of a circle is given by 2 pi times the radius. This calculation will be slightly inaccurate because the radius is slightly larger than the blade length, but it is close enough for this rough calculation.

Tip: Soulver comes with a number of constants like pi built in. You can add your own by going to the Numbers option in the menu bar and adding a new Variable. This variable will be available in all your Soulver documents.

On the next line, I’m going to use an Answer Token rather than a variable. Type DistPerMin = and then click on the Insert Answer Token menubar item. Finish by adding x (1 minute/RotationTime) after the Answer Token.

back of the envelope 2
Working with variables and Answer Tokens in Soulver.

An answer token takes the result of the line above and uses it in the current line. Answer tokens make it super easy to use information you’ve just calculated in new equations like I did here. This line calculates how far the blade travels in one minute. For me, it’s around 3700 meters.

Tip: You can also create an answer token for any line just by typing line[line number].

The next line calculates how far the blade travels in an hour. You need to multiply the previous result by 60. I did it by entering DistPerHour = [AnswerToken] x 60 however you can do it with variables instead. My result is around 226,194 meters.

To convert this to kilometres just enter DistPerHour in km on another line.

back of the envelope 3
Calculating the blade tip's distance per hour.

I now know that the blade tip travels 226 kilometres in an hour—what speed it is doing is pretty obvious. If, however, I wanted to do more calculations and I needed my result to be in kilometres per hour for them, it’s easy to convert the result.

To do so, create a new variable called SpeedPerHour and let it equal DistPerHour/hour. The result is the turbine blade tip’s speed: roughly 226 km/hour.

back of the envelope 4
The final results.

Conclusion

In this tutorial I’ve introduced you to Soulver and shown you how to go from using its most basic features to create a simple budget to using advanced features, such as variables and answer tokens, to solve multi-step physics problems. Soulver is one of the best calculator apps available; it is powerful enough to be useful but not overburdened with extra features.

Soulver has a lot more to offer—play around with it and if you’re ever stuck, explore the Reference section in the menubar or ask me a question in the comments.

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