 The word “multiply” is from the Latin multus, meaning “multi” + plex, meaning “fold”—which, in turn, is from the ProtoIndoEuropean plek, which means “to plait.”^{i}
 The word “math” is from the ProtoIndoEuropean word *me, which means “to cut grass” and is related to the word “mow.”^{e}
 Multiplication is another way to repeatedly add a number. In other words, it is repeated addition.^{a}
 The zero (0) property in multiplication means that anytime there is a zero in a problem, the answer is zero.^{m}
 In the answer to a 9’s multiplication fact, the 10s and 1s digits always add up to 9. For example, 9x4=36, so 3+6=9.^{b}
The Church of Multiplication is named after "The Miracle of the Loaves and Fish"
 In July 2015, the Church of the Multiplication was vandalized in Tabgha, Israel. Believers assert that their church is the place where Jesus multiplied five loaves of bread and two fish to feed his 5,000 followers. The Church of Multiplication is run by Benedictine Monks and is considered a significant area in Christianity.^{d}
 The commutative property of multiplication means that the order of the numbers in an equation doesn’t matter. In other words, numbers are “commutative” because they can travel back and forth like a commuter. The commutative law does not work for subtraction or division.^{b}
 The associative property of multiplication means that it doesn’t matter how numbers are grouped or which numbers are calculated first. The associative law does not work for subtraction or division.^{b}
 Gottfried Wilhelm Leibniz (1647–1716) was a universal genius who used both the cap symbol (∩) and the dot ( · ) for the multiplication symbol. While the dot is still sometimes used, the cap symbol is now most often used to indicate intersection in set theory.^{a}
 Along with addition, subtraction, and division, multiplication is one of the four elementary arithmetic operations.^{a}
 Multiplication is a type of arithmetic. Arithmetic is the study of quantity and it is the oldest and most elementary branch of mathematics. The word “arithmetic” is from the ProtoIndoEuropean root *re(i), meaning “to reason, count.” Additional types of mathematics include, algebra, geometry and topology, applied mathematics, and computational sciences.^{a}
 The inverse of multiplication is division.^{b}
Leibniz was the first to invent a calculating machine that could perform multiplication
 German polymath and philosopher Gottfried Leibniz was the first to invent a calculating machine that could handle addition, subtraction, multiplication, division, and extraction of roots. Before Leibniz, calculating machines could perform only addition and subtraction.^{a}
 Numbers to be multiplied are called the multiplier and the multiplicand, or they are sometimes both called “factors.” The result of multiplication is called a “product.”^{m}
 In A.D. 628, Indian philosopher Brahmagupta wrote a landmark text on mathematics called Br?hmasphu?asiddh?nta, which means “The Opening of the Universe.” In it, he proposes a multiplication system called gomutrika, which he says is “like the trajectory of a cow’s urine.”^{a}
 While the Babylonians were the first to use multiplication tables over 4,000 years ago, their tables were based on base 60. The oldest known tables using base 10 (similar to modern mathematics) were the Chinese, dating to about 305 B.C.^{j}
 Multiplication tables are also called the “Table of Pythagoras,” after Pythagoras of Samos, the famous Ionian Greek philosopher and mathematician.^{a}
 William Oughtred (1574–1660), a clergyman who offered free math lessons, was the first to use the symbol “?” for multiplication. Gottfried Wilhelm Leibniz, however, objected because he thought it resembled the unknown “x” too much.^{a}
 The introduction of Arabic numbers in Europe around A.D. 1200 both readily simplified multiplication and allowed for more complex calculations. Previously, medieval Europe used Roman numbers, which were straightforward for simple addition equations, but were extremely difficult to multiply or divide.^{a}
One type of calculating machine was named after a jalousie, or a type of window blind
 To perform long multiplication in medieval Europe, people used the jalousie, or gelosia, method (also known as lattice multiplication). The method was named after an iron grill or the jalousie Italian men would place over their windows to keep others from staring at their wives.^{a}
 Lattice multiplication (also known as Venetian squares, sieve multiplication, gelosia multiplication, or the Hindu lattice) has been used in many different cultures throughout history. This method of multiplication uses a lattice to multiply two multidigit numbers. While long multiplication has become more popular than the lattice method, some mathematicians find the latter easier to use.^{a}
 “Napier’s Bones” is a method of multiplication that is named after the polymath, John Napier (1550–1617). Napier developed a mechanical method for performing more complex multiplication and division problems by manipulating rods with printed digits. Most people up until this time could not multiply beyond 5 (x) 5. The rods were made of bone, ivory, wood, or metal. This method was universally popular up until the late 1800s and eventually led to the development of the slide rule.^{h}
 When multiplying an even number by 6, the product ends in the same digit as the even number. For example, 6x2=12, 6x4=24, 6x6=36, etc.^{m}
 Instead of square flashcards, some teachers use “fact triangles” cards. These threesided cards have an entire fact family on the three corners of the triangle, which helps students internalize the relationship between multiplication and division.^{n}
Common Core standards dramatically changed the way elementary schools teach multiplication
 In the United States, Common Core math standards have changed the way teachers teach multiplication. Not without controversy, common core moves students more slowly through subtraction, multiplication, and other operations that lead up to more complex math. It also moves multiplication away from the “longform method” to the “Box Method.”^{c}
 In 1980, Shakuntala Devi from India entered the Guinness Book of Records as the world’s fastest multiplier when she correctly multiplied two 13digit numbers in 28 seconds.^{g}
 Samarth Bhagyesh Patel from India holds the record for solving 10 random multiplication items correctly the fastest, with a time of 1 minute 30.60 seconds. He is just 7 years old.^{f}
 The youngest person to correctly solve a multiplication problem is 2yearold Siddhu. He correctly solved the 2, 3, and 5 multiplication tables. He can also count from 1 to 1,000 and can add any two numbers between 1 and 100.^{f}
 Italian author Andrea Camilleri once said, “In moments of crisis, all you gotta do is review your multiplication tables, and it’ll all blow over!”^{k}
 The multiplication sign “x” is also known as St. Andrews Cross because traditionally it is believed that Saint Andrew brought the little boy and his loaves and fish to Jesus who performed the Miracle of the Loaves and Fishes. Technically, using “x” in multiplication equations is considered incorrect in mathematical writing.^{l}
 Posted October 7, 2015
References
^{a} Calinger, Ronald S. 1995. Classics of Mathematics. New Jersey: Prentice Hall.
^{b} Harris, Joe. 2009. Times Tables Made Easy. New York, NY: Dorling Kindersley Limited.
^{c} Jacobs, Peter. “There’s an Amazing Way to Do Multiplication That’s Better than How You Learned in School.” Business Insider. June 5, 2014. Accessed: September 10, 2015.
^{d} Liebermann, Oren. “Israeli Police Make Arrests in ‘Loaves and Fishes’ Church Arson.” CNN. June 12, 2015. Accessed: September 10, 2015.
^{e} “Math.” Online Etymology Dictionary. 2015. Accessed September 10, 2015.
^{f} “Math World Records.” Record Setter. 2015. Accessed: September 11, 2015.
^{g} “Mental Calculation: Multiplication.” Record Holders. September 11, 2015.
^{h} Morimoto, Bertah Kugelman. “Napier’s Bones.” Computer Sciences. 2002. Accessed: September 9, 2015.
^{i} “Multiply.” Online Etymology Dictionary. Accessed: September 10, 2015.
^{j} Qiu, Jane. “Ancient Times Table Hidden in Chinese Bamboo Strips.” Nature. January 7, 2014. Accessed: September 9, 2015.
^{k} “Top Quotes about Multiplication.” Top Famous Quotes. September 11, 2015.
^{l} Turnball, Michael. “Saint Andrew.” BBC. July 31, 2009. Accessed: October 2, 2015.
^{m} WingardNelson, Rebecca. 2005. Multiplication Made Easy. Berkeley Heights, NJ: Enslow Elementary.
^{n} Zimmerman, Alycia. “Total Recall: Helping Our Students Memorize Multiplication Facts.” Scholastic. January 18, 2012. Accessed: September 9, 2015.
