How to divide many columns? : <p>I have a data frame that look like </p>

<pre><code>V1  V2    V3    V4   V5     V6    V7   V8
0   Tri1  D D   D D  D D    D D   D D   D D
0   Tri2  D D   D D  D D    D D   D D   D D
0   Tri3  D D   D D  D D    D D   D D   D D
0   Tri4  D D   D D  D D    D D   D D   D D
0   Tri5  D D   D D  D D    D D   D D   D D
</code></pre>

<p>And I want to divide column V3-V8</p>

<pre><code>V1  V2    V3 V4 V5 V6 V7 V8 V9 V10 V11 V12V13V14
0   Tri1  D  D  D  D  D  D  D  D   D   D   D  D
0   Tri2  D  D  D  D  D  D  D  D   D   D   D  D
0   Tri3  D  D  D  D  D  D  D  D   D   D   D  D
0   Tri4  D  D  D  D  D  D  D  D   D   D   D  D
0   Tri5  D  D  D  D  D  D  D  D   D   D   D  D
</code></pre>

<p>How may I do it?</p>
