( )
438=51 1650=66 809=89
6840=28 2430=54 764=72
40+30=
5+23=
55+5=
18-9=
26-4=
37+6=
53-7=
72-5=
34+8+50=
73+20-3=
47-(18-9)=
45-7-3=
25+(15-8)=
100-50+7=
=(朵)
=(个)