Abu'l-Hasan ibn Ali al-Qalasadi facts for kids

Abū'l-Ḥasan ibn ʿAlī ibn Muḥammad ibn ʿAlī al-Qalaṣādī (born in 1412, died in 1486) was a smart Muslim Arab mathematician from a region in Spain called Al-Andalus. He was especially good at a type of math called Islamic inheritance jurisprudence, which deals with how property is divided after someone dies. A historian named Franz Woepcke said that al-Qalaṣādī was very important for helping to create algebraic symbols, which are like the letters and signs we use in math today. He wrote many books about numbers and algebra, including one called al-Tabsira fi'lm al-hisab, which means "Clarification of the science of arithmetic."

Who Was Al-Qalaṣādī?

Al-Qalaṣādī was a famous mathematician who lived a long time ago. He helped make algebra easier to understand by using special symbols. Imagine trying to solve a math problem without using symbols like + or - or x! He made it possible to write math problems in a shorter, clearer way.

His Early Life and Challenges

Al-Qalaṣādī was born in a town called Baza, which was part of the Emirate of Granada in Spain. He went to school in Granada, another city, but he always helped his family back in Baza. He wrote many books and later went back to live in his hometown.

His math books were not just about numbers. They helped solve real-life problems. For example, he wrote about how to mix medicines correctly, how to figure out how much water flows through irrigation canals, and how to spot tricks with measuring tools. He also wrote math problems as fun poems, which was a tradition back then.

Around 1480, Christian armies led by Ferdinand and Isabella started to attack cities in the region. Al-Qalaṣādī helped defend Baza from the mountains nearby. Because of these conflicts, al-Qalaṣādī eventually had to leave his home. He and his family moved to Béja, a city in Tunisia, where he passed away in 1486. Later, Baza was taken over by the Christian forces.

How He Used Symbols in Math

Al-Qalaṣādī used a special way of writing algebra with symbols. Even though some people thought he invented these symbols, other mathematicians in North Africa had actually used similar ones about 100 years before him. Al-Qalaṣādī used letters from the Arabic alphabet to stand for different math ideas.

What His Symbols Meant

Here are some of the symbols he used and what they meant:

• ﻭ (wa) meant "and," which was used for addition (+).
• إلا (illa) meant "except" or "less," used for subtraction (-).
• في (fi) meant "in" or "times," used for multiplication (*).
• على (ala) meant "over," used for division (/).
• ﺝ (j) stood for jadah, meaning "root" (like a square root).
• ﺵ (sh) stood for shay' meaning "thing," which was used for a variable (like 'x' in our math).
• ﻡ (m) stood for morabba'a, meaning a square (like x²).
• ﻙ (k) stood for moka'aab, meaning a cube (like x³).
• ﻝ (l) stood for ya'adilu, meaning equality (=).

An Example of His Math

Let's look at an example. If we write the equation `2x^3 + 3x^2 - 4x + 5 = 0` today, al-Qalaṣādī would have written it using his symbols like this:

‏٢ في ش^ك ﻭ ٣ في ش^ﻡ إﻻ ٤ في ﺵ ﻭ ٥ ﻝ ٠

This shows how he used letters to represent numbers and operations, making algebra more like the way we see it today!

Images for kids

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  Map of the coasts of the kingdom of Granada by Piri Reis (16th century).

See Also

In Spanish: Al-Qalasadi para niños

• Islamic mathematics
• List of Muslim scientists