Explicație pas cu pas:
27+36-18=
63-18=
45
97-48+32= A}
49+32=
81
7x9+35=
63+35=
98
49+8x9= B}
49+72=
121
72-8x6=
72-48=
24
9x7-48= C}
63-48=
15
72+81:9=
72+9=
72:8+9= D}
9+9=
18
