Last year, the average weight of A, B, C, and D was 52 kg. This year, A's weight has increased by 1 kg, D's weight has increased by 3 kg, and the weight of the other two remains unchanged. What is the average weight of the four this year?
去年甲、乙、丙、丁四人的平均体重是52千克．今年，甲的体重增加了1千克，丁的体重增加了3千克，另外两人的体重保持不变．今年四人的平均体重是多少？
<gadget id="calculator">52 * 4</gadget>
<output>208</output>

<gadget id="calculator">208 + 1 + 3</gadget>
<output>212</output>

<gadget id="calculator">212 / 4</gadget>
<output>53</output>

<result>53</result>