Exercise 5.2

Exercise 5.2

Miscellaneous Practice problems

1. Find HCF of 188 and 230 by Euclid's game.

H.C.F. of 188 and 230

188 = 2 × 2 × 47

230 = 2 × 5 × 23

H.C.F. of (188 , 230) = 2

H.C.F. of (188, 230 − 188)

188 = 2 × 2 × 47

42 = 2 × 3 × 7

H.C.F. of (188, 42)  = 2

H.C.F. of (188 , 230) =    H.C.F. of  (188, 230 − 188)  

2. Write the numbers from 1 to 50. From that find the following.

1 2 3 4 5 6 7 8 9 10

11 12 13 14 15 16 17 18 19 20

21 22 23 24 25 26 27 28 29 30

31 32 33 34 35 36 37 38 39 40

41 42 43 44 45 46 47 48 49 50

i) The numbers which are neither divisible by 2 nor 7.

Answer: 9, 11, 13, 15, 17, 19, 23, 25, 27, 29, 31, 33, 37, 39, 41, 43, 45, 47.

ii) The prime numbers between 25 and 40.

Answer: 29, 31, 37

iii) All square numbers upto 50.

Answer: 1, 4, 9, 16, 25, 36, 49

3. Complete the following pattern

i) 1+2+3+4 = 10

2+3+4+5 = 14

 +4+5+6 = 

4+5+6+  = 

1 + 2 + 3 + 4 = 10

2 + 3 + 4 + 5 = 14

3 + 4 + 5 + 6 = 18

 4 + 5 + 6 + 7 = 22

ii) 1+3+5+7 = 16

 +5+7+9 = 24

5+7+9+  = 

7+9+  +13 = 

1 + 3 + 5 + 7 = 16

3 + 5 + 7 + 9 = 24

5 + 7 + 9 + 11 = 32

 7 + 9 + 11 + 13 = 40

iii) AB, DEF, HIJK, ___ , STUVWX

AB, DEF, HIJK, MNOPQ , STUVWX

iv) 20, 19, 17,  ,10,5

20, 19, 17, 14 , 10, 5

4. Complete the table by using the following instructions.

A: It is the 6th term in the Fibonacci sequence. 8

B: The predecessor of 2. 1

C: LCM of 2 and 3. 6

D: HCF of 6 and 20 2

E: The reciprocal of 1/5. 5

F: The opposite number of –7.  7

G: The first composite number. 4

H: Area of a square of side 3 cm. 9

I: The number of lines of symmetry of an equilateral triangle. After completing the table, what do you observe? Discuss. 3

After completing the table, what do you observe? Discuss.

Adding rows 15, 14, 16

Adding columns 14, 15, 16

Adding Diagonals 15, 16

5. Assign the number for English alphabets as 1 for A, 2 for B upto 26 for Z.

Find the meaning of 

Answer: GOOD MORNING

6. Replace the letter by symbols as + for A, – for B, × for C and ÷ for D.

Find the answer for the pattern 4B3C5A30D2 by doing the given operations.

4 B 3 C 5 A 3 0 D 2

4 – 3 × 5 + 30 ÷ 2

4 − 15 + 15 = 4

7. Observe the pattern and find the word by hiding the numbers

1H2O3W 4A5R6E 7Y8O9U?

1H2O3W  4A5R6E  7Y8O9U?

HOW         ARE         YOU?

8. Arrange the following from the eldest to the youngest. What do you get?

A − refers to parents

L − refers to you

F − refers to grandparents

I − refers to elder sister

Y − refers to younger brother

M − refers to uncle

FAMILY

Challenge problems

9. Prepare a daily time schedule for evening study at home.

5.30 p.m to 6.30 p.m − Writing Home work.

6.30 p.m to 7.30 p.m − Maths

7.30 p.m to 8.00 p.m − English

8.00 p.m to 9.00 p.m − Tamil, Science and Social science

9.00 p.m to 9.30 p.m − Drawing and extra work.

10. Observe the geometrical pattern and answer the following questions

i) Write down the number of sticks used in each of the iterative pattern.

Answer: Number of sticks 3,9,18.

ii) Draw the next figure in the pattern also find Name the total number sticks used in it.

Answer: 

Number of sticks 30.

11. Find HCF of 28,35,42 by Euclid’s game.

H.C.F. of  28, 35, 42.

28 = 2 × 2 × 7

35 = 5 × 7

42 = 2 × 3 × 7

H.C.F. of  (28, 35, 42) = 7

H.C.F. of  (28, 35 − 28, 42 − 28)

28 = 2 × 2 × 7

7 = 1 × 7

14 = 2 × 7

H.C.F. of  (28, 35 − 28, 42 − 28) = 7

H.C.F. of  (28, 35, 42) = H.C.F. of (28, 35 −28, 42 −28)

12. Follow the given instructions to fill your name in the OMR sheet.

• The name should be written in capital letters from left to right.

• One alphabet is to be entered in each box.

• If any empty boxes are there at the end they should be left blank.

• Ball point pen is to be used for shading the bubbles for the corresponding alphabets.

Answer: 

13. Consider the Postal Index Number (PIN) written on the letters as follows:604506; 604516; 604560; 604506; 604516; 604516; 604560; 604516; 604505; 604470; 604515; 604520;604303; 604509; 604470. How the letters can be sorted as per Postal Index Numbers?

Answer: 

604 is common for all postal index numbers. Compare the remaining 3 digits, 303, 470, 505, 506 (two), 509, 510, 515, 516 (four), 520, 560 (two). 

ANSWERS:

Exercise 5.2

1. 2

2. i) 9, 11, 13, 15, 17, 19, 23, 25, 27, 29, 31, 33, 37, 39, 41, 43, 45, 47 ii) 29, 31, 37 iii) 1,4, 9, 16, 25, 36, 49

3. i) 3, 18; 7, 22 ii) 3; 11,32; 11, 40

iii) MNOPQ iv) 14

4. A-8, B-1, C-6, D-2, E-5, F-7, G-4, H-9, I-3

5. GOOD MORNING

6. 4

7. HOW ARE YOU?

8. FAMILY

10. i) 3, 9, 18 ii)  30

11. 7

13. 604 is common for all postal index numbers. Compare the remaining 3 digits, 303, 470, 505, 506 (two), 509, 510, 515, 516 (four), 520, 560 (Two)