1÷[1÷(1999÷1999+1999/2000)]怎么算?

问题描述:

1÷[1÷(1999÷1999+1999/2000)]怎么算?

1÷[1÷(1999÷1999+1999/2000)]
=1÷[1÷(1+1999/2000)]
=1÷[1÷3999/2000]
=1÷2000/3999
=3999/2000