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The so called 'Pascal' triangle was known in China as early as 1261. In '1261 the triangle appears to a depth of six in Yang Hui and to a depth of eight in Zhu Shijiei in 1303. Yang Hui attributes the triangle to Jia Xian, who lived in the eleventh century. |
Vedic Maths originated from India and are based on 16 principles or 'sutras' . The section below is extracted from http://www.vedicmaths.org/Introduction/Tutorial/Tutorial.asp
The easy way to add and subtract fractions.
Use VERTICALLY AND CROSSWISE to write the answer straight down!
Multiply crosswise and add to get the top of the answer:
2 x 5 = 10 and 1 x 3 = 3. Then 10 + 3 = 13.
The bottom of the fraction is just 3 x 5 = 15.
You multiply the bottom number together.
So:
Subtracting is just as easy: multiply crosswise as before, but the subtract:
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Understanding it is not so difficult. It's simply the short cut of equivalent fractions or the LCM method that we use (just that sometimes it is not the LCM but rather CM that is being used).
E.g. The second example.
6/7 = 18/21
2/3 = 14/21
so 6/7 - 2/3 = 4/21
