Tính một cách hợp lí

1,2.154+167.−858−1,2.534−167.−718

=1,2.154−1,2.234+167.−858−167.−718

=1,2.154−1,2.234+167.−858+167.718

=1,2.154−234+167.−858+718

=1,2.−84+167.−148

=1,2.−2+16.−147.8

=−2,4+−4

=−6,4