The third grade collected 15.7 kilograms of scrap iron and steel, and the fourth grade collected 4.32 kilograms more than the third grade. How many kilograms of scrap iron and steel did the two grades collect in total?
三年级收集废钢铁15.7千克，四年级比三年级多收集4.32千克．两个年级共收集废钢铁多少千克？
<gadget id="calculator">15.7 + 4.32 + 15.7</gadget>
<output>35.72</output>

<result>35.72</result>