新人教版英語高二下module8unit3inventorsandinventions之四-資料下載頁
2024-11-17 05:59本頁面
【導(dǎo)讀】onamobilephone?phonetodoforyou?youhaveheard.thesequestions.willbuyandwhy?havenow?actasaputernow.havewiththe3-Gmobiles?4.WhyisMaryworried?spendhermoney.offer?bookholidays,airtickets,etc.ZhangJie,foradvice.MB:Hallo,isthatZhangJie?Thisis. suggest?wantyourmobiletodo?they’reagoodidea?train.marketnow.planning!phones.They“think”foryou.Thenit’llpayforyou.MB:Wow!I’mnotsureI’dbehappy. withthat!Idon’tliketheideaof. MB:Dotheyreally?Well,Inever!MB:Areyousure?Ifthat’sthecase,that’stheoneforme!Thank. ZJ:Goodbye.
【正文】 also be used to extract squareroots and cubic roots. The abacus is prepared for use by placing it flat on table or one’s lap and pushing all the beads on both the upper and lower decks away from the beam. The heads are manipulated with either the index finger or the thumb of one hand. Each head in the upper deck has a value of 5。 each beads in the lower deck has a value of 1. Beads are considered counted, when moved towards the beam that separates the two decks. After 5 heads are counted in the lower deck, the result is carried to the upper deck。 after both heads in the upper deck are counted, the result 10 is then carried to the leftmost adjacent column and so on. Floating point calculations are performed by designating a space between 2 columns as the decimalpoint and all the rows to the right of that space represent fractional portions while all the rows to the left represent whole number digits. The abacus is one of many counting devices invented to help count large numbers. The earliest counting device was the human hand and its fingers. Then, as larger quantities (larger than ten human fingers could represent) were counted, various natural items like pebbles and twigs were used to help count. Merchants who traded goods not only needed a way to count goods they bought and sold, but also to calculate the cost of those goods. Until numbers were invented, counting devices were used to make everyday calculations.
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