A total of 680 saplings need to be planted, and the garden uncle plants 90 saplings on average every day. After 5 days of planting, how many saplings are left?
一共要种680棵树苗，园林叔叔平均每天种90棵，种了5天，还剩多少棵没种？
<gadget id="calculator">90 * 5</gadget>
<output>450</output>

<gadget id="calculator">680 - 450</gadget>
<output>230</output>

<result>230</result>