4÷五分之四-五分之四÷4+4×五分之四
=4×5/4-4/5×1/4+4×4/5
=5-1/5+16/5
=5-(1/5-16/5)
=5-(-3)
=8
6.15÷2又2分之1-七分之一×(0.05+4又25分之9)
=6又3/20×2/5-1/7×(5/100+4又36/100/25)
=6又3/20×2/5-1/7×(4又41/100)
=246/100-1/7×441/100
=246/100-63/100
=183/100
八分之七×3.5+2.2×0.875+8.75×100分之43
=0.875×3.5+2.2×0.875+8.75×0.43
=8.78×0.35+8.75×0.22+8.75×0.43
=8.78×(0.35+0.22+0.43)
=8.75×1
=8.75