History of the calculator: from the abacus to the graphing calculatorFrom the abacus to algebra in your pocket, and the calculator that led to the microprocessor.Order of operations: PEMDAS, BODMAS and why 8 ÷ 2(2 + 2) starts argumentsPEMDAS, BODMAS, and why 8 ÷ 2(2 + 2) splits the internet.The slide rule: how it works, who invented it, and why it vanishedThe ruler that went to the Moon, then vanished in about four years.The abacus: history, how to use one, and the day it beat a calculator4,500 years of counting, and the day a soroban beat an electric calculator.Calculator words: how to spell words on a calculatorWhy 0.7734 says hello, 100+ words you can spell, and a word finder.How a calculator works: inside the chipOne chip, seven segments, and why 1 ÷ 3 × 3 still comes out as 1.Types of calculator: basic, scientific, graphing and moreBasic, scientific, graphing, financial, RPN, and which ones exams allow.