# TABULA/samples/value

## Values and Quantities

According to the SI Brochure… "The value of a quantity is generally expressed as the product of a number and a unit".

A TABULA quantity is the formal product of a TABULA value and a TABULA units.

There's a slight difference in terminology here.

• A TABULA value is a special case of a J value, i.e. a real (i.e. not complex) scalar number.
• A TABULA units is a utf-8 string (which has alternative formats) with a unique equivalent ASCII string.
• A TABULA quantity is a {value, units} pair.

We use units throughout as a singular noun, c/f "bellows". Thus kW is a unit, h is a unit, but [kW h] is a units.

Sometimes a units is placed in brackets to make it cohere. Then it is called nominal units.

Non-numeric values (such as strings and arrays) are not supported by TABULA as values. However a variety of value sets are supported, including integer, floating-point, Boolean, extended and rational. Also a quantity may have been formatted when you get to view it. See below.

#### Note these things about quantities

1. A given quantity, say 1 yd, doesn't have a unique {value, units} pair. Thus 1 yd and 3 ft are in every sense the same quantity!

Because TABULA works with quantities (and under-the-covers converts everything to SI base-units) this gives TABULA its biggest advantage over a heritage calculator. Although it won't let you add apples to oranges, it lets you add yards to feet – and show the result in metres. So you never need to go looking-up conversion factors and remembering which way round they go: the biggest chore of (numerate) science. All you need worry about is whether two given quantities are compatible. And TABULA warns you if they aren't.

2. A given quantity might be formatted when displayed, completely changing its appearance. Examples:

• 15%                 …equivalent to: 15 [%] or: 0.15 [/] – where [/] is the dimensionless units.
• £10.23            …equivalent to: 10.23 GBP
• 55° 17′ 24″     …equivalent to: 55.29 dms
• 23:59:59         …equivalent to: 86399 s
• YES                 …equivalent to: 1 [*] (see SAMPLE7)

## TABULA deals in Quantities, not Numbers

A heritage calculator deals in numbers, not (scientific) quantities.

Thus you can make it add the numbers: 2 and 2 to give you the number 4.

It is your responsibility to attach meanings to those numbers, and a scientific training helps you to do so. So does training in accountancy. Without any sort of (numerate) training, or effective self-teaching, your use of a calculator is unlikely to be meaningful.

With training, you will not normally add two apples to two oranges, and expect the result to have a robust meaning.

However TABULA deals in quantities, not numbers. It is designed to help people with little or no effective training to work meaningfully with quantities. Thereby to understand and solve problems in domestic resource usage, finance, trade and our relationship to our environment.

With a little experience, you will find you can approach bigger issues in the world at large, e.g. economics, ecology and government spending. Maybe even problems which extend beyond our planet, such as studying stars and the bodies in our solar system, navigating spacecraft and working with time-standards. TABULA comes with sample calculators for all these things.

## Will TABULA help me to do science?

Science is what scientists do. The rest of us listen to what scientists say as a result, and the scientists demand us to believe them.

Sometimes this is a tall order, because they tell us things we don't want to hear. Such as: drinking too much alcohol or eating too many calories is bad for us (…what's a calorie?) Or driving a gas-guzzler and being a frequent flyer is bad for the planet (…how can anything done by little me affect a great big planet?)

There's a real problem in this, which our teachers at school didn't properly prepare us for. They should either have forced us to accept that it's a mortal sin not to believe a scientist. Or equipped us with effective ways to spot when we're being told lies.

What lies? Lies by bad scientists, by good scientists employed by bad people who need to be stopped, or by bad people who want money from us. Or folk who just fancy pushing others around.

To do science you have to be scientifically trained. Untrained people don't do science - they simply amuse themselves, and occasionally delude themselves, and others. Untrained people are not equipped to tell science from twaddle.

Writers of speculative fiction know this, as do newspaper editors. Many of both sorts have stopped trying to write science and now only publish twaddle, because it's easier to write, and more entertaining to read. It's also more believable, especially if you get your beliefs ready-made, because the vendors can more easily adjust their products to fit your belief-system.

TABULA is not a substitute for scientific training.

But if you are engaged in training yourself, the hope is that you will find TABULA helps you. In ways that traditional courses of scientific training don't always provide. Or actually shun, because the ways in question are not clever enough for self-respecting adults.

But remember this…

Nobody knows if you are using TABULA, and nobody is spending money to find out. It can be your little secret and nobody cares.