Đáp án:
`6250/13299.`
Giải thích các bước giải:
Ta có: `42/46={42:2}/{46:2}=21/23.`
`250/186={250:2}/{186:2}=125/93.`
`2121/2323={2121:101}/{2323:101}=21/23`
`125125/143143={125125:1001}/{143143:1001}=125/143.`
Suy ra, `42/46 + 250/186+ (- 2121/2323)+ (- 125125/ 143143)`
`=21/23+125/93-21/23-125/143`
`=(21/23-21/23)+(125/93-125/143)`
`={17875-11625}/13299`
`=6250/13299.`