看图说成语: What chengyu do these sketches refer to (from a grade-3 语文 textbook)?

Question

This chengyu puzzle is on page 66 of a grade-3 语文 textbook (上册).

I'm fairly sure I can get the top-left one, and the middle-right one, but not the others.

I present this as a chengyu puzzle (a relatively easy one).

Question: What chengyu do these sketches refer to?

Answer 1

1 2

3 4

5 6

1. 開門見山
2. 大材小用
3. 一舉兩得
4. 三長兩短
5. 小題大做
6. 百發百中