(1)4/5÷2/3-(2/5+1/3)=6/5-2/5-1/3=4/5-1/3=7/15(2)1/4×1/4+3/4×1/4=1/4×(1/4+3/4)=1/4×1=1/4(3)(5/24+7/12-2/3)×48=5/24×48+7/12×48-2/3×48=10+28-32=6(4)1/3÷4/9+1/3÷1/4=1/3×9/4+1/3×4=1/3×(9/4+4)=1/3×25/4=25/12