Chapter 4,Grade Seven shawan Middle School 初一年级组,A What do you know about?,1 a decimal numbers 2 a pair of odd numbers 3 a fraction 4 zero 5 add;plus 6 subtract;minus 7 mutiply; times 8 divide 9 a number showing degrees 10 a percentage 11 a pair of even numbers 12 equals,A + B 0 C 5/8 D E = F 13 45 G 8 210 H 90 I J 0.82 K 45% L ,Numbers, Everyones Language,24561935891521=?,Calculating Machine,an abacus,Calculating Machine,one of the first calculating machines accurate and fast represent,beads,wires,5,7 2 4, thousands, hundreds, tens, ones,an abacus,Calculating Machine,an electronic calculator,add,subtract,multiply,divide,percentage,square root,calculate,Calculating Machine,an electronic calculator,A: What can an electronic calculator do? B: It can _, _, _ and _. A: What else can it do? B: It can calculate _ and _.,add,subtract,multiply,divide,percentages,square roots,Calculating Machine,an electronic calculator,A: What can _ do? B: It _. A: What else can it do? B: It _.,Calculating Machine,powerful a flash in your whole lifetime,a computer,Calculating Machine,A _ is a very _ calculating machine. In _, it can do a calculation that you could not do _ _.,a computer,computer powerful a flash in your whole lifetime,powerful a flash in your whole lifetime,Read the text,Competition,Answer the questions,Why do people still use abacuses today?,Because they are accurate and fast.,What can an electronic calculator do?,It can add, subtract, multiply and divide. It can also calculate percentages and square roots.,How fast can Shakuntala Devi calculate?,She can calculate like lightning.,How long can a computer do a calculation?,In a flash.,How long did the computer take to solve the difficult problem?,A minute.,What should people do to make computers calculate?,People have to_ _.,program them with instructions,What do the beads on the wires represent?,They represent _ _,ones, tens, hundreds, thousands and so on.,How many languages do you know? Everyone knows at least two his or her own language and the international language of numbers.,Numbers: everyones language,（他或她自己 的语言）,Ancient numbers In ancient times, people wrote numbers in many different ways. However, they nearly all counted in tens.,different ways of writing the number 6,（在古代）,（以很多 不同的方式）,（以十为单位）,Zero The system of numbers today consists of the numbers from 1 to 9 and 0(zero). The Indians first invented and developed the 1 to 9 system of numbers. They then invented the zero. The invention of the zero helped people write big numbers and calculate more easily. Now use each of these ten numbers once to write the biggest number. What is it?,（数字体系）,（invent. v. invention n. inventor n.）,1 ancient: many many years ago (a) 2 consists of: includes (b) 3 invented: made for the first time (b) 4 accurate: without mistakes (a) 5 percentages: amounts out of a hundred (a),C1 Find these words in the article on page 45. Read the words around them and choose the best meanings.,A B 1 international a grew bigger or stronger 2 system b a group of things working together 3 developed c count with numbers 4 calculate d strong 5 bottom e used by more than one country or nation 6 powerful f in the lowest place,C2 Find the words in Column A in the article and match them with the meanings in Column B.,1 A calculating machine using wires and heads. An _ 2 A small machine using electronic power to do calculations. A _ 3 A very powerful machine for doing calculations. A_,C3 What do the following descriptions refer to? Write down the correct names in the blanks.,calculator,computer,abacus,D Find the facts,May asks T M Li, the writer, some questions about his article on numbers. His answers are not always clear. Read the article and make Lis answers clearer. Write one word in each blank.,1 Every one knows it. Knows what? The Language of numbers.,2 Long ago, people wrote them in many different ways. Wrote what? Numbers. 3. People all count in this way. In what way? In tens. 4. The Indians invented that system of numbers. Which system of numbers? The 1 to 9 system.,5 The invention helped people write in big numbers. What invention? The invention of the zero. 6 They are fast and accurate. What? Abacuses. 7 Computers are very powerful ones. Very powerful what? Calculating machines.,Language points,1. at least 至少= not less than,We should recite at least 10 English words every day.,反义词: at most 至多,The concert hall can hold at most 1,000 people.,2. in ancient times 在古代,= long long ago,= once upon a time,In ancient times, people used stones as money.,ancient 反义词: modern 现代的,times = age n. 时代,3.