Đáp án:
1.
a) `\frac{-1}{16}` + `\frac{-2}{5}`
= `\frac{-5}{80}` + `\frac{-32}{5}`
= `\frac{-37}{80}`
b) `\frac{-1}{8}` - `\frac{3}{15}`
= `\frac{-1}{8}` - `\frac{1}{5}`
= `\frac{-5}{40}` - `\frac{8}{40}`
= `\frac{-13}{40}`
c) `\frac{-18}{10}` + `0,4`
= `\frac{-18}{10}` + `\frac{4}{10}`
= `\frac{-14}{10}`
d) `6,5` - `\frac{-1}{5}`
= `\frac{65}{10}` - `\frac{-1}{5}`
= `\frac{65}{10}` - `\frac{-2}{10}`
= `\frac{63}{10}`
e) `\frac{-2}{26}` + `4`
= `\frac{-2}{26}` + `\frac{4}{1}`
= `\frac{-2}{26}` + `\frac{104}{26}`
= `\frac{51}{13}`
f) `\frac{12}{17}` - `(``-2``)`
= `\frac{12}{17}` + `2`
= `\frac{12}{17}` + `\frac{2}{1}`
= `\frac{12}{17}` + `\frac{34}{17}`
= `\frac{46}{17}`
g) `(``\frac{3}{2}` + `\frac{5}{3}` `)` +`\frac{-1}{3}`
= `\frac{19}{6}` + `\frac{-1}{3}`
= `\frac{19}{6}` + `\frac{-2}{6}`
= `\frac{17}{6}`
h) -`(``\frac{12}{7}` - `\frac{1}{3}` `)` + `\frac{12}{7}`
= -`\frac{12}{7}` - `\frac{1}{3}` + `\frac{12}{7}`
= `(`-`\frac{12}{7}` + `(``\frac{12}{7}``)` - `\frac{1}{3}`
= `0` - `\frac{1}{3}`
= -`\frac{1}{3}`
2.
a) x + `\frac{1}{3}` = `\frac{6}{7}`
x = `\frac{6}{7}` - `\frac{1}{3}`
x = `\frac{11}{21}`
Vậy x = `\frac{11}{21}`
b) `\frac{5}{15}` - `x` = `0,25`
`\frac{5}{15}` - `x` = `\frac{1}{4}`
`x` =`\frac{5}{15}` - `\frac{1}{4}`
`x` =`\frac{1}{12}`
Vậy `x` =`\frac{1}{12}`
c) `-x` + `\frac{12}{5}` = `0,4`
`-x` + `\frac{12}{5}` =`\frac{-2}{5}`
`-x` =`\frac{-2}{5}`- `\frac{12}{5}`
`-x` =`\frac{-14}{5}`
⇒ `x` =`\frac{14}{5}`
Vậy `x` =`\frac{14}{5}`
