Tính: a) (3/4 + 1 1/2) - (5/6 : 1/3); b) [(-1/5) : 1/10] - 5/7 . (2/3 - 1/5);

a) 34:112−56:13=34:32−56.31

=34.23−56.31=12−52=−42=−2

b) −15:110−57.23−15

=−15.101−57.1015−315

=−2−57.715=−2−13

=−63−13=−73

c) −0,4+225.−23+122

=−25+125.−46+362

=−25+125.162=−24+125.136

=−25+115=−615+115=−515=−13

d) 125−0,62:49125.56−−13+12

=125−352:49125.56−−26+36

=125−352:49125.56−−26+36

=125−15252:49125.56−16

=−14252:49125.56−16

=−22.72522:7253.56−16

=−22.7254.5372.56−16

=−22.7254.5372.56−16

=46−16

=36=12