The world's first calculator — bead by bead. History from Mesopotamian dust boards to Roman counters to the Chinese suanpan, Japanese soroban, Russian schoty, and the Cranmer abacus for blind students. Master place value on the rods, complementary number tricks, addition & subtraction by sliding beads, multiplication & division, square & cube roots, anzan (mental abacus / blind calculation) — the technique speed-arithmetic champions use to outpace calculators — plus modern competitions (UCMAS, ALOHA Mind Math), classroom pedagogy, the cognitive-development research, and abacus apps. 35 units, 525 lessons.