《Unit　4　Numbers课件》初中英语牛津上海版八年级上册课件53763PPT文档格式.pptx

1、How much does a pen usually cost?What is the postcode of Ganxiang?,Reading（II）,Numbers:Everyoneslanguage,Oxford English 8A page 57 Ganxiang SchoolZhang Lili,What can we use numbers to do?,We use them totell the time show our age/countcalculate,Match,Zero is an especially important number.In ancient

2、times,there were different ways of writing numbers.Your brain may calculate better than a computerMachines make it easier for us to calculate.,Egyptian埃及的,Chinese,Roman罗马的,Greek希腊的,6,However,they nearly all counted in the same way-in tens.,Part OneAncient numbers,In ancient times，,People wrote numbe

3、rsin many different ways,What numbers are there in the system of numbersthat most of us use?What did the Indians invent first?3.What did they invent then?4.Why was it a very important invention?,Part Two,Zero,12 458936 7,1.What numbers are there in the system of numbersthat most of us use?,Part Two,

4、Zero,12 458936 7,What did the Indians invent first?The 1 to 9 system of numbers.What did they invent then?Why was it a very important invention?Because it made it easier to write big numbers and to calculate.,3 6,7,1245 89,Ancientnumbers,Modern numbers,WWhhiicchhnnuummbbeerrssaarreeeeaassiieerrtfoor

5、wcpariletceou?plaletein?different countries to understand each other?,an abacus,an electronic calculator,a computer,Part Three,Calculating machines,Why do people use them?,calculating machines,features 特点,a human brain,156 50=,Find the number that,when it is multiplied 23 times by itself,gives this

6、answer:916748676920039158098660927585380162483106680144308622 407126516427934657040867096593279205767480806790022783016354924852380335745316935111903596577547340075681688305620821016129132845546805780158806771,a=,23,a computer,Brainagainstcomputer,Part Four,a lady from India withan amazing brain.,Sh

7、akuntala Devi,How long did it take to solve this problem?,23,Shakuntala Devi:50seconds Computer:60seconds,a=916748676920039158098660927585380162483106680144308622407126516427934657040867096593279205767480806790022783016354924852380335745316935111903596577547340075681688305620821016129132845546805780

8、158806771a=?546,372,891,Which one is a more powerful calculator,a human brain or a computer?,Someone had to firstthe,computer with,instructions,and that took,had to program,many hours.No oneShakuntala.,program,A game:1,2,3,4,5,6,7,8,Numbers,Numbers are With numbers,we can We also use them to They ma

9、de it easier toIf there are no numbers,So numbers play an important part in our life.,Listen and read the text on page 57 three times.Recite new wordsFind more information about numbers.,Assignment,1.An ancient calculating machine that is still used today.Whats it?An abacus.,2.Shakuntala Devi is an

10、Indian ladywith an amazing brain.,3.Who invented the 1to 9 system of numbers?The Indians.,4.In ancient times,people counted in tens.（one word）,5.A very powerful machine for doing calculations.Whats it?A computer.,6.Shakuntalas brain works very fast.It can do a calculation like lightning.,7.What can

11、a modern electronic calculator do?It can add,subtract,multiply,and divide.It can also calculate percentages and square roots.,8.Why do people still use abacuses?They are so fast and accurate.,Complete the summary.,Ancient numbers In ancient times,people wrote numbers,but they are nearly counted.Zero

12、 Everyone uses the 1 to 9 and 0（zero）.The invented them.makes it to write big numbers and to calculate.Calculating machines The three calculating machines:the,the and the make our life easier.Brain against computer There was once a competition between an Indian and a in which the won.Computers cannot do anything by themselves.must program them first.,