Đáp án:+Giải thích các bước giải:

 `Bài    1`

`a)206,123+(44,5-6,123)`

`=206,123+44,5-6,123`

`=(206,123-6,123)+44,5`

`=200+44,5=244,5`

`2)105,681+(6,5-23,681)`

`=105,681+6,5-23,681`

`=(105,681-23,681)+6,5`

`=82+6,5=88,5`

`3)98,512-26,8+12,488`

`=(98,512+12,488)-26,8`

`=111-26,8`

`=84,2`

`4)26,287-78,14+13,813`

`=(26,287+13,813)-78,14`

`=40,1-78,14=-38,04`

`5)120,548-25,98+(-75,548)`

`=120,548-25,98-75,548`

`=(120,548-75,548)-25,98`

`=45-25,98=19,02`

`6)(-37,129)+16,87-86,871`

`=-(37,129+86,871)+16,87`

`=-124+16,87=-107,13`

`7)25,158-(-25,136)+36,842-16,136`

`=25,158+25,136+36,842-16,136`

`=(25,158+36,842)+(25,136-16,136)`

`=62+9=71`

`8)18,269+15,789+(-65,269)-(-67,211)`

`=18,269+15,789-65,269+67,211`

`=(15,789+67,211)-(65,269-18,269)`

`=83-47=36`

`9)25,6+(-15,236)+17,236-(-25,4)`

`=25,6-15,236+17,236+25,4`

`=(25,6+25,4)+(17,236-15,236)`

`=51+2=53`

`10)3,258+(26,124+(-15,258))+64,876`

`=3,258+26,124-15,258+64,876`

`=(26,124+64,876)-(15,258-3,258)`

`=91-12=79`

` Ngochoa#~~9`