=(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