Chapter Four Numbers: 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% a decimal number 8. subtract; minus 2. a protractor 9. multiply (for measuring angles) 10. divide 3. a pair of odd numbers 11. a number showing 4. compasses degrees (for drawing circles) 12. a percentage 5. a fraction 13. a pair of even 6. zero numbers 7. add; plus 14. equals d m h k e g l j n c b i a f

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

equal(s) v. add v. Add…and…. plus prep. …plus…is…. + add v. Add…and…. plus prep. …plus…is…. - subtract v. Subtract…from…. minus prep. …minus…is…. equal(s) v. is =

multiply v. Multiply…by…. …multiplied by…is…. times prep. …times…is…. × multiply v. Multiply…by…. …multiplied by…is…. times prep. …times…is….

divide v. Divide…by…. …divided by…is…. ÷

statements 陈述，说明 instructions 指示，指令 Add one and one 1+1 One plus one equals two. 1+1=2 prep. Two minus one equals one 2-1=1 Two multiplied by three is six. 2*3=6 adj. Four divided by two is two. 4÷2=2 statements 陈述，说明 Add one and one 1+1 Subtract one from two 2-1 Multiply two by three 2*3 Divide four by two 4÷2 v. instructions 指示，指令

＋ plus  minus × multiply/multiplied  divide/divided 2 ＋ 3 ＝ 5 5  2 ＝ 3 2 × 3 ＝ 6 6  2 ＝ 3 2 plus 3 equals/is 5. 5 minus 2 equals/is 3. 2 multiplied by 3 equals/is 6 6 divided by 2 equals/is 3.

8 1 2 4 A game: 24 points ＋ plus minus  × multiply  divide 8  2 ＝6 equals/is 6. 6 × 4 ＝24 6 multiplied by 4 equals/is 24. 2 4 24 1 ＝24 24 divided by 1 equals/is 24.

A game: 24 points 5 2 ＋  ×  plus minus multiply divide 1 7

A game: 24 points 4 5 ＋  ×  plus minus multiply divide 9 5

A game: 24 points 3 2 ＋  ×  plus minus multiply divide 6 8

A game: 24 points 2 6 ＋  ×  plus minus multiply divide 4 8

Homework Recite the second paragraph Do exercise 2