第1章：有向數 .hk
[pic]
[pic]
1. Among the following numbers, which of them are positive? Which of them are negative? Write them down on the appropriate boards.
(2 (1.2 (4.5 [pic] [pic] (8
(3.2 (0.3 [pic] (9.2 (1 (100
[pic]
2. Determine whether each of the following statements is correct. If yes, put a ‘(’ in the box; otherwise put a ‘(’.
(a) (2, (30, (56 and (100 are negative numbers. □
(b) (12, (20, (77 and (14 are directed numbers. □
(c) ‘0’ is a positive number. □
(d) ‘(4’ reads as ‘positive four’. □
(e) ‘(3’ reads as ‘minus three’. □
[pic]
3. Answer the following questions in positive or negative numbers.
(a) If the monthly salary of George increases by $800, find the change in monthly salary.
(b) If the selling price of a model car drops by $35, find the change in selling price.
(c) If a helicopter descends 100 m, find the change in distance above the ground.
(d) If the Hang Seng Index rises by 120, find the change in the Hang Seng Index.
4. Fill in the blanks with suitable positive or negative numbers.
(a) If (100 m represents walking 100 m forward, then represents walking 65 m backward.
(b) If (8 m represents 8 m above the water level, then represents 10 m below the water level.
(c) If (4 represents the drop of class ranking from last time by 4, then represents the rise of class ranking from last time by 6.
(d) If ($300 represents a withdrawal of $300, then represents a deposit of $450.
5. If ‘−$1’ represents the decrease of $1 in monthly salary, express the following in positive or negative numbers.
(a) An increase of $100 in monthly salary
(b) A decrease of $200 in monthly salary
(c) An increase of $555 in monthly salary
(d) A decrease of $480 in monthly salary
6. If ‘(8 cm’ represents the increase in length of 8 cm, what is the meaning of ‘(5 cm’?
7. If ‘($100’ represents a loss of $100, what is the meaning of ‘($2 500’?
[pic]
8. It is known that the New Year’s Day is on 1st January. Suppose ‘+1 day’ represents a day after the New Year’s Day of this year, express the following dates in positive or negative numbers.
(a) 7th January of this year
(b) 30th December of last year
(c) 25th December of last year
(d) 12th January of this year
9. Given that the temperature of city A is 0(C, the temperature of city B is 20(C higher than that of city A, and the temperature of city C is 15(C lower than that of city A.
(a) Which city has the highest temperature? Which city has the lowest temperature?
(b) Express the temperatures of city B and city C in positive or negative numbers.
[pic]
[pic]
10. According to the number line below, fill in the blanks with suitable numbers.
[pic]
11. Complete the following.
(a) On a horizontal number line, positive numbers are located on the side of zero and negative numbers are on the side of zero.
(b) A is a number with a positive or negative sign before it.
12. Complete the following.
(a) (((1) (
(b) (((4) (
(c) (((5) (
(d) (((8) (
[pic]
13. According to the number line below, find the values of points A to E.
[pic]
14. Mark the following points on the number line.
A ’ 3, B ’ (4, C ’ (2, D ’ 1, E ’ 0
[pic]
15. Compare each of the following groups of numbers, and fill in the blanks with ‘(’ or ‘(’ appropriately.
(a) (6 □ (11 (b) (6 □ (2
(c) (4 □ (5 (d) (12 □ (7
(e) 0 □ (17 (f) (8 □ 0
16. According to the number line below, fill in the blanks with ‘>’or ‘ ................
................
In order to avoid copyright disputes, this page is only a partial summary.
To fulfill the demand for quickly locating and searching documents.
It is intelligent file search solution for home and business.