Teacher Li bought a teacher's house and paid in installments. One payment method is to pay 210,000 yuan in the first year, and 30,000 yuan per year thereafter; the other payment method is to pay 60,000 yuan per year for the first half of the time, and 45,000 yuan per year for the second half of the time. The payment amount and payment time of the two payment methods are the same. If one payment is made, the house payment can be reduced by 48,000 yuan. Now Mr. Li pays off the house payment in one lump sum, how much is the house payment?
李老师购买了一套教师住宅，采取分期付款的方式．一种付款方式是开始第一年先付21万元，以后每年付款3万元；另一种付款方式是前一半时间每年付款6万元，后一半时间，每年付款4.5万元．两种付款方式的付款钱数和付款时间相同．假如一次付款，可少付房款4.8万元．现在李老师一次付清房款，要付房款多少万元？
<gadget id="calculator">21 - 3</gadget>
<output>18</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(1/2) * 6</gadget>
<output>3</output>

<gadget id="calculator">(1/2) * 4.5</gadget>
<output>2.25</output>

<gadget id="calculator">2.25 - 3</gadget>
<output>-0.75</output>

<gadget id="calculator">3 + (-0.75)</gadget>
<output>2.25</output>

<gadget id="calculator">18 / 2.25</gadget>
<output>8</output>

<gadget id="calculator">8 - 1</gadget>
<output>7</output>

<gadget id="calculator">7 * 3</gadget>
<output>21</output>

<gadget id="calculator">21 - 4.8</gadget>
<output>16.2</output>

<gadget id="calculator">21 + 16.2</gadget>
<output>37.2</output>

<result>37.2</result>