Grandpa Zhang participated in the provincial rural medical insurance. In February, he was hospitalized due to illness and spent a total of 12,300 yuan in medical expenses. According to the provisions of the insurance, the state will compensate 70% of the personal hospitalization for more than 300 yuan. How much should Grandpa Zhang pay for the hospitalization?
张爷爷参加了省农村医疗保险，二月份他因病住院，共花去医药费12300元．按保险条款规定，个人住院超过300元部分国家按70%给予补偿，张爷爷这次住院应自付医药费多少元？
<gadget id="calculator">12_300 - 300</gadget>
<output>12_000</output>

<gadget id="calculator">70 / 100</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">12_000 * (7/10)</gadget>
<output>8_400</output>

<gadget id="calculator">12_300 - 8_400</gadget>
<output>3_900</output>

<gadget id="calculator">3_900 + 300</gadget>
<output>4_200</output>

<result>4_200</result>