6 consecutive natural numbers, the sum of the first three numbers is 90, what is the sum of the last three numbers?
6个连续的自然数，前三个数的和是90，那么后三个数的和是多少．
<gadget id="calculator">90 / 3</gadget>
<output>30</output>

<gadget id="calculator">30 + 3</gadget>
<output>33</output>

<gadget id="calculator">33 * 3</gadget>
<output>99</output>

<result>99</result>