将下列各式写成省略加号的和的形式,并按括号内要求交换加数的位置.
1个回答

(1) (+16)+(-29)-(-7)-(+11)+(+9);(使符号相同的加数在一起)

=16-29+7-11+9

=(16+7+9)+(-29-11)

=32+(-40)

=-8

(2) (-3.1)-(-4.5)+(+4.4)-(+1.3)+(-2.5);(使和为整数的加数在一起)

=-3.1+4.5+4.4-1.3-2.5

=(-3.1-1.3+4.4)+(4.5-2.5)

=0+2

=2

(3) (+1又1/4)-(+5)+(-1/3)-(+1/4)+(-5又2/3);(使分母相同或便于通分的加数在一起)

=1又1/4-5-1/3-1/4-5又2/3

=(1又1/4-1/4)+(-1/3-5又2/3)-5

=1+(-6)-5

=-5-5

=-10

(4) (-2.4)-(-4.7)-(+0.5)+(+3.4)+(-3.5).(使计算简便)

=-2.4+4.7-0.5+3.4-3.5

=(-2.4+3.4)+(-0.5-3.5)+4.7

=1+(-4)+4.7

=-3+4.7

=1.7