School mathematics refresher: when faced with a calculation that looks like it could be tackled multiple ways, use BODMAS to help clear it up (See PEMDAS at the end).

BODMAS is an acronym (as opposed to an initialism) that tells you the order of operations to tackle in a calculation.

BODMAS stands for Brackets, Order/Indices, Division, Multiplication, Addition, and Subtraction. So in 2 + 4 x 2 you don't end up with 6 x 2 = 12 but instead, 2 + 8 = 10

BODMAS is generally built into calculators (you can search 2 + 4 x 2 in Google to see). If you need additions or subtractions to be carried out first you can surround them in brackets eg (2 + 4) x 2

I always learned it as BODMAS, but many people told me they learned this as PEMDAS. The idea is the same just the words are different, and the ordering of Division and Multiplication, which are interchangeable:

PEMDAS: Parentheses, Exponents, Multiplication, Division, Addition, and Subtraction

BODMAS

The Gini coefficient, or Gini index, is a common way to gauge income or wealth inequality within a population.

The coefficient gives a single number showing how equal a distribution is. For example, in a population where everyone earns the same amount the Gini coefficient would be 0 — total equality — and in a population where one person earned all of the population's money, the Gini coefficient would be 1 (sometimes expressed as 100%) — maximum inequality. In practice all countries' Gini coefficients are somewhere in between, at around 0.25 to 0.5 after taxes.

Like any simple measure the Gini has its difficulties, like being easily misinterpreted when compared, but is still widely used. The BBC has a short piece on its history and an alternative measure called the Palma ratio.

Of course, we have some high profile zillionaires at the moment. You might like this old sketch of wealth inequality in America.

The Gini coefficient

This negative is the score, the print is the performance. This memorable analogy is from Ansel Adams, one of the foremost American photographers. From the negative captured by the camera, Ansel would experiment with cropping, dodging and burning (lightening and darkening) to create the final print. We have a large print of moon and half dome in our hallway. It's a reminder to me that what the camera captured directly isn't the final piece. You still have the performance to perform.

The analogy works beyond photographs. A recipe, a script, a joke, or a business idea all still need the right performance.

Prints and performances