直接写得数

18÷6=____

180÷60=____

下列二次根式中，与 $\sqrt{3}$ 能合并的是（   ）

等差数列{a_n}中，若a₄+a₆+a₈+a₁₀+a₁₂=120,则$a_9-\frac{1}{3}{a}_{11}$的值是（    ）

量一量，估一估．

1个1元硬币的面积大约是多少平方厘米？再估计一下100个1元硬币的面积大约是____平方厘米．

 根据对话内容，用方框中所给单词的适当形式填空，每词限用一次。

water    no    Earth    it    for

Bill: I saw a great programme on TV about space yesterday evening.
Tony: What is ____ about?  
Bill: Scientists have discovered ____ on Mars.
Tony: Really? That's very fantastic. Have they discovered life on Mars?
Bill: Well, they're looking____  life but they haven’t found anything yet.
Tony: I know there's ____ life on the moon.
Bill: Yes, that's right. So far there's only life on ____ .
Tony: Are we alone with so many stars in the universe?
Bill: I am interested in it, so I want to be a scientist when I grow up.
Tony: I wish you will.