55- 44 =66 - 55 =77 - 66 =93 - 63 =
22 - 11 =33- 22 =44- 33 =88 - 77 =
42 + 8=43 + 7 =48 + 12=35 + 35 =
10 + 10=23+ 23 =3×15 =64+ 26 =
25 + 25 =24 + 23 =24 + 26 =38 + 12 =
2×10=50 - 20 =20 - 20 =21 - 21 =
45- 44 =13×3 =38 - 18=77 - 77 =
56 + 44 =45+ 55 =24 + 16 =50×2=
18+ 82=50+ 15 =20×2 =12×2 =
48 - 18 =39- 15 =87 - 63 =53- 27 =
