苏联解体后，世界政治格局的演变趋势（    ）

30×9=____       90÷3=____          22×4=____          200÷4=____

55÷5=____       3＋400=____         62－7=____          6×700=____

0÷800=____      42×2=____          360÷9=____         3×6＋4=____

$\frac{1}{4}$ ＋ $\frac{2}{4}$ =____      $\frac{4}{5}$ － $\frac{4}{5}$ =____        $\frac{4}{7}$ ＋ $\frac{2}{7}$ =____        1－ $\frac{5}{6}$ =____