4△4=4*5*6*75△5=5*6*7*8*9相除=4*5*6*7/(5*6*7*8*9)=4/(8*9)=1/18
4△4 = 4×5×6×75△5 = 5×6×7×8×9所以(4×5×6×7)÷(5×6×7×8×9) = 4/(8×9) = 4/72 = 1/18
(4△4)÷(5△5)=(4*5*6*7)/(5*6*7*8*9)=4/(8*9)=1/18