The ratio of Xiao Ming and Xiao Hua's savings is 3:7. If Xiao Ming deposits another 400 yuan, it will be as much as Xiao Hua's savings. How much money did Xiao Ming save?
小明和小华存钱数的比是3：7，如果小明再存入400元，就和小华的存钱一样多．小明原来存了多少钱？
<gadget id="calculator">7 - 3</gadget>
<output>4</output>

<gadget id="calculator">400 / 4</gadget>
<output>100</output>

<gadget id="calculator">100 * 3</gadget>
<output>300</output>

<result>300</result>