There are 22 people on the playground, 9 girls are skipping rope, 13 boys are skipping rope, how many more boys are skipping rope than girls?
操场上有22人，有9名女生在跳绳，13名男生在跳绳，跳绳的男生比女生多几人？
<gadget id="calculator">13 - 9</gadget>
<output>4</output>

<result>4</result>