and B save 640 yuan in total, B and C save 600 yuan in total, and A and C save 440 yuan in total. How much does A save? what is the correct formula
甲、乙两人共储蓄640元，乙、丙两人共储蓄600元，甲、丙两人共储蓄440元．甲储蓄多少元？正确算式是多少
<gadget id="calculator">640 + 600 + 440</gadget>
<output>1_680</output>

<gadget id="calculator">1_680 / 2</gadget>
<output>840</output>

<gadget id="calculator">840 - 600</gadget>
<output>240</output>

<result>240</result>