bài 1 )
a) `2/3` - `5/9` x `3/4` `2/3` - `15/36`
= `2/3` - `5/9` x `3/4` = `2/3` - `5/12`
= `2/3` - `5/12` = `8/12` - `5/12
= `2/3` - `5/12` - = `1/4`
=`1/4``
b) `2/5` + `1/4` : `3/8`
= `2/5` + `2/3`
= `16/15`
c) `1/2` + `1/3` : `1/6`
=`1/2` + `2`
= `1/2` + `4/2`
= `5/2`
d) `7/9` x `3/14` : `5/8`
= `1/6` : `5/8`
= `4/15`
e) 79 x `11` + `2800` x `40`
= `869` + `112000`
= `112869`
f)26475 x 36 - 76945 : 5
= 953100 - `15389`
= 937711
bài 2) xem ảnh
