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Percents, fractions, and decimals

By |2017-07-29T16:45:17+00:00July 29th, 2017|Math|

Each penny is 1% of a dollar. Percent comes from the Latin words "per cent". That means "out of a hundred," like there are 100 cents in a dollar. So "ten per cent" means ten out of every hundred. A dime is ten percent of a dollar. A dollar is ten percent of [...]

Simple equations – Algebra

By |2017-07-27T23:23:08+00:00July 27th, 2017|Math|

Simple equations on a graph When we learn to add and subtract, multiply and divide, we think of numbers as being all along the number line. But in algebra we think about numbers as being in a plane. Picture two number lines crossing each other at zero. The one that goes up and down we call the y-axis and the one that goes from side [...]

Medieval Islamic mathematics

By |2018-04-24T08:21:16+00:00July 27th, 2017|Islam, Math|

Indian numbers About 630 AD, just before the Islamic empire got started, people in West Asia learned from traders or traveling scholars about "Arabic" numbers. This new way of writing numbers really came from India. The Arabic word for numbers, in fact, is hindsah, which means "from India". The new numbers included for the first time a way to write [...]