Xiao Ming started to write big characters on January 1st, and wrote 4 big characters on the first day. After that, he wrote the same number of big characters every day compared with the previous day. As a result, he wrote a total of 589 big characters in the whole month. How many more big characters did Xiao Ming write every day compared to the previous day?
小明从一月一日开始写大字，第一天写了4个，以后每天比前一天多写相同数量的大字，结果全月共写589个大字，小明每天比前一天多写几个大字？
<gadget id="calculator">2 / 31</gadget>
<output>2/31 = around 0.064516</output>

<gadget id="calculator">589 * (2/31)</gadget>
<output>38</output>

<gadget id="calculator">38 - 4</gadget>
<output>34</output>

<gadget id="calculator">34 - 4</gadget>
<output>30</output>

<gadget id="calculator">31 - 1</gadget>
<output>30</output>

<gadget id="calculator">30 / 30</gadget>
<output>1</output>

<result>1</result>