$#Leam$
`Bài` `1 :`
`A = 5240 - ( 254 - 427 ) + ( 573 - 325 ) - 421`
`= 5240 - 254 + 427 + 573 - 325 - 421`
`= 5240 + ( - 254 - 325 - 421 ) + ( 427 + 573 )`
`= 5240 + ( - 1000) + 1000`
`= 5240`
`B = 455 - ( - 432 - 576 ) - ( - 568 + 1576 )`
`= 455 + 432 + 576 + 568 - 1576`
`= 455 + ( 432 + 568) + ( 576 - 1576 )`
`= 455 + 1000 - 1000`
`= 455`
`C = - ( 475 - 324 + 538 ) + 1250 - ( 1324 - 38 ) `
`= - 475 + 324 - 538 + 1250 - 1324 + 38`
`= - 475 + ( 324 - 1324 ) + ( - 538 + 38 ) + 1250`
`= - 475 + ( - 1000 ) + ( - 500 ) + 1250`
`= - 975 + 1250 `
`= 275`
CHUCBANHOKTOT ^^
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