al-Khwarizmi, the Digits and the Word "Algorithm"

What you'll learn

• Roman numerals have no zero and no place value, so adding them is a real headache.
• Our digits 0–9 use place value: the 3 in 30 means 3 tens, in 300 it means 3 hundreds. Zero holds an empty place (3_5 → 305).
• This system was built in India; in 628 Brahmagupta wrote rules for zero (a number minus itself is zero).
• Around 820, Baghdad's House of Wisdom was full of scholars translating Greek, Persian and Indian books.
• Muhammad ibn Musa al-Khwarizmi wrote a book on calculating with the Indian numerals, step by step. Centuries later its Latin translation turned his name into "Algoritmi" → algorism → algorithm. His book al-Jabr gave us the word "algebra".
• In 1202 Fibonacci spread the "Hindu–Arabic numerals" across Europe.
• An algorithm = a recipe of exact steps. Column addition with a carry is one! Your phone runs billions of tiny steps a second, and counts with place value in binary: places 8 · 4 · 2 · 1, so 1011 = 8 + 2 + 1 = 11.