1. Tính nhẩm:

a) 27 x 10 = 270 ;        72 x 100 = 7200;            14 x 1000 = 14000

86 x 10 = 860;             103 x 100 = 10300;         452 x 1000 = 452000

358 x 10 = 3580 ;       1977 x 100 = 197700;     300 x 1000 = 300000

b) 80 : 10 = 8;            400 : 100 = 4 ;             6000 : 1000 = 6

300 : 10 = 30;            4000 : 100 = 40;          60000 : 1000 = 60

2000 : 10 = 200;     40000 : 100 = 400 ;       600000 : 1000 = 600

c) 64 10 = 640;       32 x 100 = 3200 ;           95 x 1000 = 95000

640 : 10 = 64 ;         3200 : 100 = 32;           95000 : 1000 = 95

2. Tính :

a) 63 x 100 : 10 = 6300 : 10

                          = 630

b) 960 x 1000 : 100 = 960000 : 100

                                = 9600

c) 79 100 : 10 = 7900 : 10

                       = 790

d) 90000 : 1000 x 10 = 90 x 10

                                  = 900

3. Viết số thích hợp vào chỗ chấm:

a) 160 = 16 x 10                       b) 8000 = 8 x 1000

4500 = 45 x 100                           800 = 8 x 100

9000 = 9 x 1000                           80 = 8 x 10

c) 70000 = 70 x 1000                d) 2020000 = 202 × 10000

70000 = 700 x 100                        2020000 = 2020 x 1000

70000 = 7000 x 10                       2020000 = 202000 x 10

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