用加法计算:
用乘法计算:
×2 4× ×18
÷ × ÷
1× = ×8 = × = ÷ =
×100= ÷ = × = 0.5÷ =
① × + ×
② + ÷
③ ×17-
④ ÷ ×
⑤ ÷( + )
⑥99×