There are 3 integers, if 5 times the second number is 4 times the difference between the first number and 1, and 5 times the third integer is 4 times the difference between the second number and 1, then the first What is the minimum value of the number.
有3个整数，如果第2个数的5倍是第1个数与1的差的4倍，第3个整数的5倍是第2个数与1的差的4倍，那么第1个数的最小值是多少．
<gadget id="calculator">5 / 4</gadget>
<output>5/4 = around 1.25</output>

<gadget id="calculator">16 * (5/4)</gadget>
<output>20</output>

<gadget id="calculator">20 + 1</gadget>
<output>21</output>

<result>21</result>