Near-number arithmetic, part one: addition and subtraction

The first of a three-part lesson on near-number arithmetic is now online!  This first video covers addition and subtraction; next will come a video on multiplication and division, and finally a video discussing and connecting all of the ☆-forms.  Key learning goals are:

• how binary arithmetical operations operate on near-numbers (one pair of slices at a time, on all pairs of numbers, one from each slice);
• familiarity with addition of basic near-numbers: finite + finite, finite + infinite, and infinite + infinite, and subtraction via adding the negative;
• ☆-forms for addition and subtraction, including the fundamental ☆-form, +∞ + –∞.