Chapter FourNumbers: Everyone’s language

Match the words with the pictures, signs and numbers:

a. ＋ b. 0 c. 5/8 d. e. f. ＝ g. 13 45

h. i. 8 210 j. 90 k. × l.

m. 0.82 n. 45%1. a decimal number 8. subtract; minus2. a protractor 9. multiply (for measuring angles) 10. divide3. a pair of odd numbers 11. a number showing4. compasses degrees (for drawing circles) 12. a percentage5. a fraction 13. a pair of even6. zero numbers 7. add; plus 14. equals

mh

gl

cb

a

d

ke

jn

if

Read the article and tell whether the following statements are true or false.( ) 1. In ancient times, numbers were written in different ways, but counting was nearly always in tens.( ) 2. Everyone uses the numbers system 1 to 9 plus 0 (zero).( ) 3. The numbers system was invented by the Chinese.( ) 4. Zero makes it even more difficult to write big numbers and to calculate.( ) 5. People use abacuses, calculators and computers to calculate.( ) 6. Calculators cannot calculate percentages and square roots.( ) 7. Computers can work only when human beings program them with instructions.

T

T

F

F

T

F

T

add v. Add…and….

plusplus prep. …plus…is….

subtractsubtract v. Subtract…from….minusminus prep. …minus…is…. equal(s) v.

is

multiply v.

Multiply…by….

…multiplied by…is….

times prep.

…times…is….

divide v.

Divide…by….

…divided by…is….

One plus one equals two. 1+1=2 prep.Two minus one equals one 2-1=1 prep.Two multiplied by three is six. 2*3=6 adj.Four divided by two is two. 4÷2=2 adj.

Add one and one 1+1•Subtract one from two 2-1Multiply two by three 2*3Divide four by two 4÷2

v.

statements陈述，说明

instructions指示，指令

＋ ×

plus minus multiply/multiplied divide/divided

2 ＋ 3 ＝ 5 5 2 ＝ 32 × 3 ＝ 66 2 ＝ 3

2 plus 3 equals/is 5.5 minus 2 equals/is 3.2 multiplied by 3 equals/is 66 divided by 2 equals/is 3.

A game: 24 points

8 1

2 4

8 2 ＝ 68 minus 2equals/is 6.

＋ ×

plus minus multiply divide

24 1 ＝ 2424 divided by 1 equals/is 24.

6 × 4 ＝ 24 6 multiplied by 4 equals/is 24.

A game: 24 points

5 2

1 7＋

×

plus

minus

multiply

divide

A game: 24 points

4 5

9 5＋

×

plus

minus

multiply

divide

A game: 24 points

3 2

6 8＋

×

plus

minus

multiply

divide

A game: 24 points

2 6

4 8＋

×

plus

minus

multiply

divide

Homework Recite the second paragraph Do exercise 2