6×6= 29-6= 26+30= 3×4+20=
73-25= 5×3= 58+20= 7+20+30=
2×6= 46-7= 3×4= 2×5+45=
21
23
41
43
33
53
35
55
时=分
3020g=kg
680m2=hm2