Near-number arithmetic, part two: multiplication and division

The second of a three-part lesson on near-number arithmetic is now online, covering multiplication and division; next will come 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 multiplication of basic near-numbers: finite × finite, finite × infinite, and infinite × infinite, and division via multiplying by the reciprocal;
• ☆-forms for multiplication and division: 0⁺× +∞, +∞/+∞, and 0⁺/0⁺
• The number zero times anything—including +∞—is simply zero.