Bài 2. Tính :

a) 8dm + 2dm =

10dm - 9dm =

b) 3dm + 2dm =

9dm + 10dm =

16dm - 2dm =

35dm - 3dm =

Giải

a) 8dm + 2dm = 10dm

10dm - 9dm = 1dm

b) 3dm + 2dm = 5dm

9dm + 10dm = 19dm

16dm - 2dm = 14dm

35dm - 3dm = 32dm