can someone explain the calculations? i need to find the biggest gain (which is 0.006) but i dont know how to calculate it. where do the numbers come from? thank you.

Bull Currency Spreads Two call ptions on Australian dollars are currently available. - First option premium $.019 Second option premium $.015 First option strike price = $.64 second option strike price = $.65 $.600 $.640 $.645$.650 $.700 Buy the call with lower X .019 .019 .014 .009 .041 Sell the call with higher X .015 .015 .015 .015 035 .004 .004 .001.006 .006 Net