过已知直线外的一点作已知直线的平行线,能作无数条. .
= ÷28=七成五= %= (填小数).
÷5=6: =0.6== :15.
3÷4= (填分数)= (填小数)
= ÷ == (最后一空填小数)
1.75=7÷ = =28÷ = .