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It may be useful to be aware that the difference between two successive square numbers is the sum of their respective square roots. Hence, if one knows that 12 × 12 = 144 and wish to know 13 × 13, calculate 144 + 12 + 13 = 169. This is because (x + 1) 2 − x 2 = x 2 + 2x + 1 − x 2 = x + (x + 1) x 2 = (x − 1) 2 + (2x − 1)
In chemistry, the last digit of the CAS registry number (a unique identifying number for each chemical compound) is a check digit, which is calculated by taking the last digit of the first two parts of the CAS registry number times 1, the previous digit times 2, the previous digit times 3 etc., adding all these up and computing the sum modulo 10.
The book contains specific algebraic explanations for each of the above operations. Most of the information in this article is from the original book. The algorithms/operations for multiplication, etc., can be expressed in other more compact ways that the book does not specify, despite the chapter on algebraic description. [a]
Mental calculation is said to improve mental capability, increases speed of response, memory power, and concentration power. Many veteran and prolific abacus users in China, Japan, South Korea, and others who use the abacus daily, naturally tend to not use the abacus any more, but perform calculations by visualizing the abacus.
A mental calculator or human calculator is a person with a prodigious ability in some area of mental calculation (such as adding, subtracting, multiplying or dividing large numbers). In 2005, a group of researchers led by Michael W. O'Boyle, an American psychologist previously working in Australia and now at Texas Tech University , has used MRI ...
Quizlet was founded in 2005 by Andrew Sutherland as a studying tool to aid in memorization for his French class, which he claimed to have "aced". [ 6 ] [ 7 ] [ 8 ] Quizlet's blog, written mostly by Andrew in the earlier days of the company, claims it had reached 50,000 registered users in 252 days online. [ 9 ]
Scott Flansburg (born December 28, 1963) is an American dubbed "The Human Calculator" and listed in the Guinness Book of World Records for speed of mental calculation. He is the annual host and ambassador for The National Counting Bee, a math educator, and media personality. He has published the books Math Magic and Math Magic for Your Kids. [1]
The Chisanbop system. When a finger is touching the table, it contributes its corresponding number to a total. Chisanbop or chisenbop (from Korean chi (ji) finger + sanpŏp (sanbeop) calculation [1] 지산법/指算法), sometimes called Fingermath, [2] is a finger counting method used to perform basic mathematical operations.