Ws4 Rational Numbers

Date:

______/______/ 2009

Marks

Worksheet 4: Rational Numbers 1

Basic Question Consider the following numbers 2 1 −3 , 1, , π , 2, − 4, 3 27 Write down a) the integers, b) the irrational numbers, c) the prime numbers.

2 , 3.33, 5

3

[Xin Min Sec School/2007] 2 Ans: (a) 1, 2, −4,3 (b) π , (c) 2, 3 5 2

Intermediate Question Write down the following numbers in descending order. −1.6 , − 1.62 , −0.4 , −1.62 , −

3 10

[Anglican High School/2008] Ans: − 3

3 , −0.4 , − 1.62 , −1.6 , −1.62 10

Intermediate Question

5 1 − 7 3 Evaluate 2 4 × 5 9 Solution: 5 1 15 − 7 − 7 3 = 21 2 4 8 × 5 9 45 8 8 = ÷ 21 45 8 45 = × 21 8 1 =2 7

[Xin Min Sec School/2007] 1 Ans: 2 7

© Victoria School Math Department

4

Intermediate Question

2  4  − × 1 − 2  3  5  Evaluate (a) 5 2 − ÷4 7 7

2

1  1 2 −3  3 2 (b)  . 1  1 3 −  −2  2  3

[Cedar Girls’ Sec School /2008] Solution: (a)

2  4 2  1  − × 1 − 2  − ×  −  3  5  = 3  5 5 2 5 30 − ÷4 − ÷ 7 7 7 7 2 = 15 5 7 − × 7 30 2 = 15 1 − 6 2 −6 = × 15 1 4 =− 5

(b)

2

1  1 7 7 2 −3   −  2 3 2  3 = 7 7 1  1 + 3 −  −2  2 3 2  3

2

 14 − 21    6  = 21 + 14 6

2

2

 7 −  6 = 35 6 49 6 = × 36 35 7 = 30

Ans: (a) −

4 7 (b) 5 30

© Victoria School Math Department