## Binary Division

This is the fourth of a four part series on “pencil and paper” binary arithmetic, which I’ve written as a supplement to my binary calculator. The first article discusses binary addition; the second article discusses binary subtraction; the third article discusses binary multiplication; this article discusses binary division.

The pencil-and-paper method of binary division is the same as the pencil-and-paper method of decimal division, except that binary numerals are manipulated instead. As it turns out though, binary division is simpler. There is no need to guess and then check intermediate quotients; they are either 0 are 1, and are easy to determine by sight.

## Binary Multiplication

This is the third of a four part series on “pencil and paper” binary arithmetic, which I’m writing as a supplement to my binary calculator. The first article discusses binary addition; the second article discusses binary subtraction; this article discusses binary multiplication.

The pencil-and-paper method of binary multiplication is just like the pencil-and-paper method of decimal multiplication; the same algorithm applies, except binary numerals are manipulated instead. The way it works out though, binary multiplication is much simpler. The multiplier contains only 0s and 1s, so each multiplication step produces either zeros or a copy of the multiplicand. So binary multiplication is not multiplication at all — it’s just repeated binary addition!

## One Hundred Acorns in Binary

Today is the 100th day of school at my son’s elementary school. I’ve had my binary influence on prior 100th day projects, and this year was to be no different. But alas, his class is not doing one this year. I didn’t want to waste the acorn tops we saved though, so I made my own 100th day project (well not quite — I didn’t glue them):

## Binary Subtraction

This is the second of a four part series on “pencil and paper” binary arithmetic, which I’m writing as a supplement to my binary calculator. The first article discusses binary addition; this article discusses binary subtraction.

The pencil-and-paper method of binary subtraction is just like the pencil-and-paper method of decimal subtraction you learned in elementary school. Instead of manipulating decimal numerals, however, you manipulate binary numerals, according to a basic set of rules or “facts.”

## Exploring Binary On My Apple II

I’m reading Steve Wozniak’s 2006 book “iWoz” and this line got me wondering about my own Apple II:

“In every speech I give, I talk to people who are still running Apple IIs, and they say those machines are still running after this many years.”

So I got it out of the attic and powered it up. The dozen or so dead keys notwithstanding, it still works — after 30 years!