1. Write:
add a thousand :
    a)   
            2 145, 3 145, ...................., ...................., ....................,...................  
              ......................, ........................, ......................,.............................. .  
    b) add 100  
                     1 732, 1832, ..................., ..................., ......................,......................  
                       ......................., ......................., ........................,.................... .  
    c) add 10 :  
                  3 968, 3978...................., ......................, ......................,....................,  
                    .........................., ......................., ........................,.................... .  
    d) add 1:  
                8 995, 8996.................., ........................, .......................,......................,  
                  ..........................., ........................, ..........................,.................... .  

2.Calculate

 

3 000 + 372 = ..........................  
4 000 + 500 = ..........................  
2 000 +   50 = ..........................
8 472 -    472 = ..........................  
7 600 -    600 = ..........................  
7 600 - 7 000 = .........................