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# Unit 4(第三课时)

Unit 4 Numbers
Cecily

abacuses
An old kind of calculating machine.

calculators

electronic calculators

computers
a kind of calculating machine.

Words and expressions

? ? ? ? ? ? ? ? ? ?

? ? ? ? ? ? ? ? ? ?

decimal number odd numbers even numbers zero fraction percentage cardinal numbers ordinal numbers degree decimal point

? ? ? ? ? ? ? ? ? ?

? ? ? ? ? ? ? ?

square square root add v. plus prep. subtract v. minus. prep. multiply v. times prep. divide v. equal v. total of…

Competition

8
7

1

2 3

6

5

4

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 Shankuntala’s brain take to solve the difficult problem?

? 50 seconds.

How long did the computer take to solve the difficult problem?

? A minute.

What should people do to make computers calculate?

? People have program them to_______________ with instructions __________________.

How many kinds of calculators do the text mention? What are they?

? Four. Abacuses, electronic calculators, computers and human brains.

a. accurate electron ic powerful amazing

wire percentage square root calculator calculatio n

subtract multiply divide
calculat e program

Words and phrases from GRAMMAR, P61

? ? ? ? ? ?

even number fraction percentage decimal number odd number degree

? ? ? ? ? ?

? ? 13.5o ? ? 32.48 ? ? 345.472 ? ? 30.5o
? 3/5 ? 7/10 ? 32%

thirty point five degree thirteen point five degree thirty-two point four eight three hundred and forty-five point four seven two

? three-fifths ? seven-tenths ? thirty-two percent

? 200/100 ? two hundred-hundredths

Let’s read out the numbers ? ? ? ? ? ? ? ? 2.66 26% 2/6 75% 75o 90o 1/8 0.75 ? ? ? ? ? ? ? ? two point six six twenty-six percent two-sixths seventy-five percent seventy-five degree ninety degree one-eighth zero point seven five

? 数字的表达方式
? 1. 100 以上的基本的基数词 ? 100 – hundred. 百 ? 1,000 – thousand 千 ? 1,000,000 – million 百万 ? 10,000,000 — ten million 千万 ? 100,000,000 – hundred million 一亿 ? 1000 million = billion 十亿 ? 2. 十位数与百位数之间加 and。如： ? 257 two hundred and fifty-seven ? 681 six hundred and eighty-one ?

? ? ? ? ? ? ?

3. 百万、万、千之间不用and。如： 3,499 three thousand four hundred and ninety-nine. 53,684 fifty-three thousand six hundred and eighty-four 472,958 four hundred and seventy-two thousand nine hundred and fifty-eight ? 8,769,316 ? eight million seven hundred and six-nine thousand three hundred and sixteen.

? ? ? ?

80,000,000 8千万 eighty million 800,000,000 8亿 eight hundred million

? decimal numbers 小数 ? 0.65 ? zero / naught point six five. ? 0.0089 ? zero / naught point zero zero eight nine ? 1.35 ? one point three five ? 45.345 ? forty five point three four five 注：小数点后面的数字要一一读出。

? a fraction 分数

? 1/3 one third ? 2/3 two thirds ? 1/4 a / one quarter or one fourth ? 3/7 three sevenths ? 3/ 10 three tenths ? 2 1/5 two and one-fifth ? 注：分数表达法： ? 分子用基数词，分母用序数词。 分子>1,分母要加s。代分数的话，整数和 分数中间加and

? ? ? ? ? ? ? ? ?

a percentage 百分数 0.68% zero point six eight percent 6% 6 percent 20% twenty percent 369% three hundred and sixty nine percent

? 284,653 ? two hundred and eighty-four thousand six hundred and fifty-three ? 1,000,000 ? one million

? 5,367,982 ? five million three hundred and sixtyseven thousand nine hundred and eightytwo

? What’s the difference between

add v. 加 plus prep. 加 subtract v. 减 minus prep.减
multiply v. 乘 divide v. 除

? Add 12 to 8, you can get 20.
? 12 plus 8 is (equals) 20. ? ? 20 减 12 等于 8. Subtract 12 from 20, you can get 8. 20 minus 12 is (equals) 8.

? 4 乘 5 等于20. ? Multiply 4 by 5, you can get 20.

? 4 multiplied by 5 equals (is) 20.
? ? ? 30 除以 6 等于 5. Divide 30 by 6, you can get 5. 30 divided by 6 is (equals) 5.

? 15+24=39 ? Add 15 to 24, you get 39. ? 15 plus 24 is 39.
? ? 39 – 15 = 24 Subtract 15 from 39, you get 24 39 minus 15 is 24

? 12×4= 48 ? Multiply 12 by 4, you get 48. ? 12 multiplied by 4 equals 48.

? ? ?

36÷3= 12 Divide 36 by 3, you can get 12 36 divided by 3 is 12

even numbers 偶数 add / plus 加 odd numbers 奇数 subtract/minus减 divide 除 multiply, times 乘 equals 等于

? Some more Ex. on calculations:

? 3 + 7=10
? 35 –6= 29 ? 14×2= 28 ? 545÷45= 12.11

? Keys: ? 3 + 7=10 ? 3 added to 7equals 10.
? 3plus 7equals 10.

? 35 –6= 29 ? Subtract six from thirty-five. 35 minus 6 is 29.

? 14×2= 28 ? Multiply fourteen by two. ? 14 multiplied by 2 equals 28. ? 545÷45= 12.11 ? Divide five hundred and forty-five by fortyfive, and you get twelve point one one.

? 545 divided by 45 equals 12. 11.

0.54

50% 213

420

40°

3/5

79

40

25°

3/7

17

1,000

76%
27

75% 852 7.7
6.5 2005 32.5 °

21.13 160 ° 7/9 57.22

420, 40, 1,000, 852, 1. Even numbers______________________________ 213, 79,

17, 27, 2005 2. Odd numbers_______________________________ 3/5, 3/7, 7/9 3. Fractions__________________________________ 50%, 76%, 75% 4. Percentages_________________________________
6. Decimal numbers____________________________ 0.54, 7.7, 21.13, 6.5

40°,25°,160 °, 32.5 5. Numbers showing degrees_____________________ °

Task 2, Say out the following numbers 166 1502 36% 0.75 5.05 41° 27° 2006 1/5 3/5 one hundred and sixty six one thousand, five hundred and two thirty six percent zero point seven five five point 0 five forty one degree twenty seven degree two thousand and six. / two 00 six one-fifth three-fifths

? 579 ? 2,564

? 35,456
? 358,721 ? 3,356,323

? five hundred and seventy-nine ? two thousand five hundred and sixty-four ? thirty-five thousand four hundred and fifty-six ? three hundred and fifty-eight thousand seven hundred and twenty-one ? three million three hundred and fifty-six thousand three hundred and twenty-three

1. 房号： 1103 ---- Room 1103 2. 班级、年级---- Class 6, Grade 9 /Form Three 3. 时间： 6：50 ---- six fifty; ten to seven 4. 年、月、日： 1986/12/6 --- December the sixth, nineteen eighty-six

5. 温度： 36°C ---- thirty-six Celsius degree
6. 序数： 12th — twelfth 14th —fourteenth

?

? ? ? ? ? ? ? ? ?

Write down the cardinal and ordinal numbers ? ones teens tens ? one eleven ten first twelve twenty second ? two ? three thirteen thirty third fourth ? four fourteen forty ? five fifteen fifty fifth ? six sixteen sixty sixth seventh ? seven seventeen seventy eighth ? eight eighteen eighty ? nine nineteen ninety ninth

Complete the sentences with cardinal or ordinal numbers.
Position in class May: 1 May is first. Alan: 2 Alan is second. Danny: 3 Danny is third. June: 4 June is fourth. Peter: 12 Peter is twelfth. Alice: 19 Alice is nineteenth. Steve: 28 Steve is twenty-eighth.

Say these ordinal numbers. p60
st 1 th 8 st 21

2nd 3rd 4th 5th

9th 12th 13th th 20

22nd 23rd 100th

Speaking A Talk time
A4 Say these telephone numbers.

When we say telephone or ID card numbers, we say each number separately. For 0 we say zero or oh. When two of the same number are together, we can say double before the number.

2921 5143 2565 1351 2471 0122 2339 4166 2010 5100 2724 5566 2978 1121 2356 4399

Homework
? 1.Finish Grammar practice book. ? 2.Review the notebook.