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Decimal Numbers. Geneviève Boulet, Ph.D. Overview of Decimals. History Language Extending the numeration chart Real Numbers in Decimal Notation Fractions to Decimals Decimals to Fractions. History. Decimal notation La Disme , published in1585 by Simon Stevin
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Decimal Numbers Geneviève Boulet, Ph.D
Overview of Decimals • History • Language • Extending the numeration chart • Real Numbers in Decimal Notation • Fractions to Decimals • Decimals to Fractions
History • Decimal notation • La Disme, published in1585 by Simon Stevin • Integration of fractions into the base-ten numeration system
Language • 0.5 is “five tenths” and not “zero point 5” • Misadaptation: the case of “and” • Enunciate well: “ths” (“ièmes” in French) • In SI, both the comma and the period are used: 12.345 or 12,345
Extendingthe Numeration chart What is 3.725? What is it counting? How many tenths in 3.725? Hundredths? Thousandths? Tens? Hundreds? Thousands?
Fractions to Decimals • Find and equivalent decimal fraction (a fraction with a denominator that is a power of 10): • If an equivalent decimal fraction cannot be found, use division 3 ÷ 4
Decimals to fractions • If the period is 0, express the decimal number as a decimal fraction:
decimals as Fractions • If the period is not zero, use the card and registry method. 0.3333... Is what fraction?