The students went to plant trees, planted 9 trees in each row, and just planted all the saplings in row 4. Use these saplings to plant 6 rows, how many trees should be planted in each row?
同学们去种树，每行种9棵，4行正好把树苗都种完．用这些树苗种6行，每行需要种几棵？
<gadget id="calculator">9 / 6</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">4 * (3/2)</gadget>
<output>6</output>

<result>6</result>