The textbooks for the second volume of the fourth grade are 6.79 yuan for Chinese, 7.43 yuan for mathematics, 8.21 yuan for English, and 6.57 yuan for science. How much will it cost to buy these four textbooks?
四年级下册的教科书，语文6.79元、数学7.43元、英语8.21元、科学6.57元，如果买这四本教科书一共需要多少钱？
<gadget id="calculator">6.79 + 7.43 + 8.21 + 6.57</gadget>
<output>29</output>

<result>29</result>