5/12×1/13-1/4÷13 = 1/78=0.012820512820513
(5/12) x (1/13) - (1/4) ÷ 13= (5/12) x (1/13) - (1/4) x (1/13)= (5/12 - 3/12) x (1/13)= (1/6) x (1/13)= 1/78