Q 4) Solve the following:

1. A machine on an average manufactures 2825 screws a day. How many screws did it produce in the month of January 2013

Answer: Cross Multiply for answer

In month of January there are 31 days

1 day ======= 2825 screws

31 days ========? screws

? x 1 = 2825 x 31 = 87575

2. The length, breath and height of a room are 835 cm, 675 cm and 450 cm respectively. Find the longest tape which can measure the three dimensions of the room exactly

(AS I HAVE ALREADY MENTIONED IN MY MATH NOTES, STUDENTS OF STD VI ARE NOT READY TO SOLVE WORD PROBLEMS OF LCM AND HCF)

Answer: The question here is finding the HCF of number 835, 675 and 450

   5   | 835

 167 | 167 

         |   1

5 x 167

NOTE: IT IS EXTREMELY DIFFICULT FOR STUDENTS TO FACTORISE 167 because then you will need prime numbers greater than 10 and less then 20. So as i have

said before please give sums where number is less than 100 and prime factors that students can easily use will be 2,3,5 and 7.

3 | 675

3   |  225

  3 |  75 

  5 | 25

 5  | 5

   | 1 

3 x 3 x 3 x 5 x 5

2 | 450

 3 |    225

3  |   75

5  | 25

5 |  5

   | 1

2 x 3 x 3 x 5 x 5

So Highest common factor is 5. So longest tape which can measure the three dimensions of the room exactly is 5 cm.

3.A. Use number line and add the following integers.

i) 9 + (-6) = 9 - 6 = 3

ii) -1 + (-7) = -1 -7 = -8

3.B. Match the following:

1. 3 sides of equal length   =    Equilateral

2. 2 sides of equal length    =    Isoceles

3.   3 acute angles              =    Acute angle  (ASK TEACHER FOR VERIFICATION)

4.   1 right angle                = A right angled

4.  Three boys step off together from the same spot. There steps measure 63 cm, 70 cm and 77 cm respectively. What is the minimum distance each should cover so that all can occur the distance in complete steps?

Answer: This is the LCM Problem.

7 | 63     70   77

 2  |  9       10   11 

 3   |    9       5     11 

3     |     3       5     11

5    |     1       5     11

11   |     1      1       11

     |      1       1       1

LCM = 7 x 2 x 3 x 3 x 5 x 11 = 6930 cm

Note: THIS MULTIPLICATION IS TOUGH FOR STD VI

5. The cost of a purse is Rs. 250 and a steel tiffin box is Rs. 290. Find the total cost of 11 purses and 19 steel tiffins.

Answer:     1 purse ===== Rs. 250

                  11 purses ====== ?

? x 1 = 250 x 11 = 2750 Rs.

1 tiffin ===== Rs. 290

19 tiffin ====== ?

? x 1 = 290 x 19 = 5510 Rs.

Total cost = 2750 + 5510 = Rs. 8260

6. Draw a circle of radius 3 cm and mark

a. Its center

b.  a radius

c.  a segment

d. a sector