Participated in 4 math tests with an average score of 78. He wants to improve the average score of 5 times to 80 points or above after the next math test, so what is the minimum score he needs to take in the next test?
参加了4次数学测验，平均成绩是78分．他想在下次数学测验后，将5次的平均成绩提高到80分或80分以上，那么，在下次测验中，他至少要考多少分？
<gadget id="calculator">80 * 5</gadget>
<output>400</output>

<gadget id="calculator">78 * 4</gadget>
<output>312</output>

<gadget id="calculator">400 - 312</gadget>
<output>88</output>

<result>88</result>