A:Ca(OH)2
B:CH3COOH
C:BaSO4
D:CH3COONa
472-398=
1112 + 56 =
84.84 ÷ 0.84=
25% × 4=
5.2+8=
2.5-0.36-0.64=
625 × 512 =
5×4 ÷ 5×4=
3.54+0.74-2.54=
38 × 54 + 54 × 58 =