Yang Yang's current weight is 43 kg, which is 1.4 kg more than 13 times his birth weight. How many kilograms did he weigh at birth?
杨扬现在的体重是43千克，比他出生时体重的13倍还多1.4千克．他出生时体重多少千克？
<gadget id="calculator">43 - 1.4</gadget>
<output>41.6</output>

<gadget id="calculator">41.6 / 13</gadget>
<output>3.2</output>

<result>3.2</result>