There are 3 iron blocks, and every two are weighed together, and their weights are 56 kg, 59 kg, and 60 kg respectively. How much is the heaviest iron block heavier than the lightest iron block?
有3个铁块，每两个合称一次，称得它们的重量分别是56千克、59千克和60千克，最重的铁块比最轻的铁块重多少千克．
<gadget id="calculator">56 + 59 + 60</gadget>
<output>175</output>

<gadget id="calculator">175 / 2</gadget>
<output>175/2 = around 87.5</output>

<gadget id="calculator">(175/2) - 56</gadget>
<output>63/2 = around 31.5</output>

<gadget id="calculator">(175/2) - 60</gadget>
<output>55/2 = around 27.5</output>

<gadget id="calculator">(63/2) - (55/2)</gadget>
<output>4</output>

<result>4</result>