5×4
78+16=
7×9=
62+31=
47-29=
6×7=
7×5=
40-17=
5×8=
6×2=
算式:( )×( )=( )
口诀:
4×3
2×3
①600﹣300÷20×5
②(4.8﹣3.8÷2)×0.3
③3.45×99×2+6.9
④(8+ )÷4
⑤ ÷9+ ×
⑥ ÷[ ×( - )]