Bài 1, 2, 3 trang 45 SGK Toán 3

Đề bài

1. Số ?

1km = ..hm                       1m = …dm           

1km =…m                         1 m =…cm

1 hm =…dam                    1 m = ..mm

1hm =…m                         1 dm =…cm

1 dam =…m                      1 cm =…mm.

2. Số ?

8 hm = ….m                                8 m = ….dm

9 hm = ….m                                6 m = ….cm

7 dam = ….m                              8 cm = ….mm

3 dam = ….m                              4 dm = ….mm

3.Tính (theo mẫu) :

32 dam x 3 =   96dam                    96 cam : 3 = 32 cm.

25 m x 2 =                                     36 hm : 3 =

15 km x 4 =                                   70 km : 7 =

34 cm x 6 =                                   55 dm : 5 =

Hướng dẫn giải

3.Tính (theo mẫu) :

32 dam x 3 =   96dam                    96 cam : 3 = 32 cm.

Lời giải chi tiết

1. 

1km = 10 hm                        1m = 10 dm           

1km =1000 m                       1 m =100 cm

1 hm =10 dam                      1 m = 1000 mm

1hm =100 m                         1 dm =10 cm

1 dam =10 m                        1 cm =10 mm.

2.

8 hm = 800 m                              8 m = 80 dm

9 hm = 900 m                              6 m = 600 cm

7 dam = 70 m                              8 cm = 800 mm

3 dam = 30 m                              4 dm = 400 mm.

3.

25 m x 2 =     50 m                              36 hm : 3 = 12 hm

15 km x 4 =    60 km                           70 km : 7 = 10 km

34 cm x 6 =    204 cm                          55 dm : 5 = 11dm.