There are three grades in Guangming Primary School. The first grade students account for 25% of the total number of students in the school. The ratio of the number of students in the second grade to the third grade is 3:4. It is known that there are 40 fewer students in the first grade than in the third grade. How many students are there in the first grade?
光明小学有三个年级，一年级学生占全校学生人数的25%，二年级与三年级学生人数的比是3：4，已知一年级比三年级学生少40人，一年级有学生多少人．
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (1/4)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">3 + 4</gadget>
<output>7</output>

<gadget id="calculator">4 / 7</gadget>
<output>4/7 = around 0.571429</output>

<gadget id="calculator">(3/4) * (4/7)</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">(3/7) - (1/4)</gadget>
<output>5/28 = around 0.178571</output>

<gadget id="calculator">40 / (5/28)</gadget>
<output>224</output>

<gadget id="calculator">224 * (1/4)</gadget>
<output>56</output>

<result>56</result>