The average height of the three girls in the fourth class of the third grade is 130cm. To make the average height reach 135cm, you can find the number of boys whose height is 138cm.
三年级四班三个女生的平均身高是130cm，要使平均身高达到135cm，可以找身高是138cm的男生多少名．
<gadget id="calculator">135 * 3</gadget>
<output>405</output>

<gadget id="calculator">130 * 3</gadget>
<output>390</output>

<gadget id="calculator">405 - 390</gadget>
<output>15</output>

<gadget id="calculator">138 - 135</gadget>
<output>3</output>

<gadget id="calculator">15 / 3</gadget>
<output>5</output>

<result>5</result>