In the activity of "Giving Love - Donating to the Earthquake-stricken Areas" in a certain elementary school, the five classes of the sixth grade donated a total of 630 yuan, of which the first class donated 140 yuan, the second class donated 10 yuan less than the first class, and the third class donated the total number of grades 20%, the ratio of donations from Class 4 to Class 5 is 6:7. How much do you want to donate to class four?
某小学在"献爱心--为地震灾区捐款"活动中，六年级五个班共捐款630元，其中一班捐款140元，二班比一班少捐款10元，三班捐款数是年级总数的20%，四班与五班捐款数之比是6：7．求四班捐款多少元？
<gadget id="calculator">140 - 10</gadget>
<output>130</output>

<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">630 * (1/5)</gadget>
<output>126</output>

<gadget id="calculator">630 - 140 - 130 - 126</gadget>
<output>234</output>

<gadget id="calculator">6 + 7</gadget>
<output>13</output>

<gadget id="calculator">6 / 13</gadget>
<output>6/13 = around 0.461538</output>

<gadget id="calculator">234 * (6/13)</gadget>
<output>108</output>

<result>108</result>