Câu 1, 2, 3, 4 trang 8 Vở bài tập (SBT) Toán 2 tập 1

1. a) Số?  

\(1dm\,\,\, = \,\,\,\,cm\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,10cm\,\,\, = \,\,\,\,dm\)

    b) Viết 1dm, 2dm vào chỗ chấm thích hợp:

 2. Số?

3.  Điền dấu >, <, =

\(\eqalign{
& 2dm\,\,\,\, = \,\,\,....\,\,\,cm\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,20cm\,\,\,\, = \,\,\,....\,\,\,dm \cr
& 3dm\,\,\,\, = \,\,\,....\,\,\,cm\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,30cm\,\,\,\, = \,\,\,....\,\,\,dm \cr
& 5dm\,\,\,\, = \,\,\,....\,\,\,cm\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,50cm\,\,\,\, = \,\,\,....\,\,\,dm \cr
& 9dm\,\,\,\, = \,\,\,.....\,\,cm\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,90cm\,\,\,\, = \,\,\,....\,\,\,dm\, \cr} \)

4. Viết cm hoặc dm vào chỗ chấm thích hợp:

BÀI GIẢI

1.

a)    \(1dm\,\,\, = \,\,10\,\,cm\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,10cm\,\,\, = \,\,\,1\,dm\)

b)

2. 

 \(\eqalign{
& \,\,\,\,\,\,\,\,2dm\,\,\,\, = \,\,\,20\,\,\,cm\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,20cm\,\,\,\, = \,\,\,2\,\,dm \cr 
& \,\,\,\,\,\,\,\,3dm\,\,\,\, = \,\,\,30\,\,cm\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,30cm\,\,\,\, = \,\,\,3\,\,\,dm \cr 
& \,\,\,\,\,\,\,\,5dm\,\,\,\, = \,\,\,50\,\,\,cm\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,50cm\,\,\,\, = \,\,5\,\,\,dm \cr 
& \,\,\,\,\,\,\,9dm\,\,\,\, = \,\,\,90\,\,cm\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,90cm\,\,\,\, = \,\,\,9\,\,\,dm \cr} \)

3.  

\(\eqalign{
& 8dm\,\,\,\, = \,\,\,80cm\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,9dm\,\,\,\, - \,\,\,4dm\,\,\, > \,\,\,\,40cm\, \cr
& 3dm\,\,\,\, > \,\,\,20cm\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,1dm\,\,\,\, + \,\,\,4dm\,\,\, < \,\,\,\,60cm\, \cr} \)

4. 

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