`a ) 18000 : 45 + 18000 : 54 - 18000`
`= 18000 : ( 45 + 54 ) - 18000`
`= 18000 : 99 - 18000`
`= 181,81... - 18000`
`text{ĐỀ SAI}`
`b ) ( 400 × 5 - 1000 × 2 ) × ( 4 + 8 + 12 + ... + 32 + 36 )`
`= ( 2000 - 2000 ) × ( 4 + 8 + 12 + ... + 32 + 36 )`
`= 0 × ( 4 + 8 + 12 + ... + 32 + 36 )`
`= 0`
`c ) 98 - 88 + 78 - 68 - 58 - 48`
`= 10 + 78 - 68 - 58 - 48`
`= 88 - 68 - 58 - 48`
`= 20 - 58 - 48`
`text{ĐỀ SAI}`
`#dtkc`