The 10×10 number grid is a useful aid for adding and subtracting two-digit numbers. Children should be encouraged to try these operations mentally using the grid as often as possible

• 9 added to 28 gives  .

• The sum of 9 and 44 is  .

• Reducing 98 by 34 gives  .

• 4 and 37 more is  .

• Take 35 away from 83. We get .

Find My Food

Hey! I have something more interesting for you. Ma told me, there are things to eat in some rooms. Help me find those room numbers. Mark them in my home. See what you get!

     

     E.g., 47 = 37 + 10

37 + 9 = 

    

 62 - 30 = 

     

    = 46 + 28

     

     

 = 87 - 14

62 - = 43

45 + = 99

 + 26 = 75

 - 1 = 1

36 = - 8

43 + = 74

100 =  + 50

57 - = 20

Adding Made Easy

Anisha bought apples for 37 rupees. Raja bought bananas for 21 rupees. The woman selling fruits said:
37 is 30 and 7
21 is 20 and 1
So 37 and 21 make 58. 

        

    

   

    

  

Can you do it another way? Say how.

See if you can do the same with these sums.

 

 

MANGO CHILLI GAME

Use a pair of dice (or ten tamarind seeds). Keep a different coloured button for each player. If you reach a mango you go forward (+). If you step on a chilli you have to go back (-). See who reaches back home first !

  

 

  

  56 + 21 = -------------- + --------------+ -----------+ ------------

             = -------------+ ------------+ -------------

             = ------------+ ----------- = ------------

        

         

Now work out the steps in your mind.
Write the answers directly in the boxes.

33 + 42 =	= 33 + 27	55 + 25 =
19 + 61 =	= 34 + 63	67 + 25 =
= 48 + 42	= 53 + 64	72 + 56 =

 

                                                                                         Let Me Tell You a Story..........

Once a baby lion lost his way in the jungle. He started crying and called out for his mother. An old deer took pity on him. He took him to his place. But the other deer got really scared. So did their other friends - rabbits, squirrels and birds. A lion among us! Oh, no! He will eat up our babies. The old deer said - don't worry. I will warn him about this. In the morning the baby lion thanked every one and started to leave, But a rabbit said - wait, he cannot go like this! Let us count to see if he has done any mischief. We should be 240 in all. Let's count.

         

              

            

        

In the chapter Fun with Numbers, children would have made token cards. The same token cards should be used for exercises in addition before children do written sums.

Let's add and find out how many deer and rabbits were there...

   

                                                                         

  Putting all the  s together,we get fifteen  s

   Ten  s make one  and we are left with five

    

      Now putting together all the  s, we get seven  s

      So total number of    and     = 75

      Similarly we add the number of birds and number of squirrels.   

      Putting all the  s together first and grouping them

        

                                                                               

           Then putting together the  s and lastly the  s we get  

          So together birds and squirrels were 162, and deer and rabbits were 75.
            The old deer said - we were 240 in number, now how many are we in all?

               

            To find out, do the addition in the box below:

              

              

How Many Bulbs?

• A factory makes 270 bulbs on the first day. On the second day it makes 123 bulbs.
  
  How many bulbs does the factory make altogether?