(1)71+64÷16
=71+4
=75
(2)8.6×3-4.2
=25.8-4.2
=21.6
(3)[5/7]×(1-[3/5])
=[5/7]×[2/5]
=[2/7]
(4)[9/17]×18+16×[9/17]
=(18+16)×[9/17]
=34×[9/17]
=18
(5)[2/3]÷[([1/2]+[1/3])×[2/5]]
=[2/3]÷[[5/6]×[2/5]]
=[2/3]÷[1/3]
=2
(1)71+64÷16
=71+4
=75
(2)8.6×3-4.2
=25.8-4.2
=21.6
(3)[5/7]×(1-[3/5])
=[5/7]×[2/5]
=[2/7]
(4)[9/17]×18+16×[9/17]
=(18+16)×[9/17]
=34×[9/17]
=18
(5)[2/3]÷[([1/2]+[1/3])×[2/5]]
=[2/3]÷[[5/6]×[2/5]]
=[2/3]÷[1/3]
=2