=(89+ 1 1)+( 124+26)

= 100+ 150

=250

2、875- 177-23

=875-( 177+23)

=875-200

=675

3、 147×8+8×53

=( 147+53)×8

=200×8

= 1600

4、0.87×0.25+0.087×7.5

=0.87×0.25+0.85×0.75

=0.87×(0.25+0.75)

=0.87× 1

=0.87