8.1除以4.2减0.3除以2.1加7分之3怎么算

8.1除以4.2减0.3除以2.1加7分之3怎么算
8.1除以4.2减0.3除以2.1加7分之3怎么算

8.1除以4.2减0.3除以2.1加7分之3怎么算
8.1除以4.2减0.3除以2.1加7分之3
=8.1÷4.2-0.6÷4.2+3/7
=(8.1-0.6)÷4.2+3/7
=7.5÷4.2+3/7
=12.5/7+3/7
=15.5/7
=31/14

8.1/4.2-0.3/2.1+3/7
=27/14-1/7+3/7
=27/14-2/14+6/14
=31/14