In order to prevent H7N7 virus infection, the experimental primary school used disinfectant and water in a ratio of 1:200 to make disinfectant. If 402 kg of disinfectant is prepared, how many kilograms of disinfectant are needed?
实验小学为了预防H7N7病毒感染，用消毒液与水按1：200的比例配制成消毒水．如果配制402千克消毒水，需要消毒液多少千克？
<gadget id="calculator">1 + 200</gadget>
<output>201</output>

<gadget id="calculator">1 / 201</gadget>
<output>1/201 = around 0.004975</output>

<gadget id="calculator">402 * (1/201)</gadget>
<output>2</output>

<result>2</result>