Ws3 Integers

Date:

______/______/ 2009

Marks

Worksheet 3: Integers 1

Basic Evaluate [ 3 × (22 – 9) ] – 121 ÷ 11 × 6 Solution: 3 × (2 2 − 9)  − 121 ÷ 11× 6 = 3 × ( 4 − 9 )  − 11 ×6 = 3 × ( −5 )  − 66 = −15 − 66 = −81

[Cedar Girls’ Sec School/2007] Ans: −81

2

Intermediate Evaluate 3

(a) 4 − ( −4 ) − ( −7 ) (b)

2

2

43 − 4 × ( −2 ) − 2 × ( −8 )

Solution: (a)

4 − ( −64 ) − ( 49 ) = 4 + 64 − 49 = 19

(b)

2

43 − 4 × ( −2 ) − 2 × ( −8 ) = 64 − 4 × 4 + 16 = 64 − 16 + 16 = 64 =8

Ans: (a) 19 (b) 8

© Victoria School Math Department

3

Intermediate The temperature at the top of the mountain 8200 m above the ground is – 6° C and the temperature on the ground is 26° C. If the temperature decreases uniformly as the height increases, find the height above the ground where the temperature is 4° C. Solution: Height increase for every temperature decrease

= 8200 ÷ ( 26 − ( −6 ) ) = 8200 ÷ 32 = 256.25°C Height above the ground = 256.25 × ( 26 − 4 ) = 5637.5m

[Crescent Girls’ School/2008] Ans: 5637.5 m

4

Intermediate Evaluate (a)

13 − (− 2 ) (− 1) × 10 + (− 5) × (− 4 )

(b)

2

3

2 − 3 + (− 1)

3

3 − 2 − (− 1)

[Cedar Girls’ Sec School/2008]

[Xin Min Sec School/2007]

Solution: (a)

13 + 2 1×10 + 20 15 = 30 1 = 2

(b)

2 − 3 + ( −1) 3 − 2 − ( −1)

3

3

2 − 3 + (−1) 1 − (−1) −1 + (−1) = 2 −2 = 2 = −1 =

Ans: (a)

1 , −1 2

© Victoria School Math Department