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几道简算题81.(362+548×361)/(362×548-186)2.(1988+1989×1987)/(1988×

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几道简算题8
1.(362+548×361)/(362×548-186)
2.(1988+1989×1987)/(1988×1989-1)
3.(204+584×1991)/(1992×584―380)―1/143
几道简算题81.(362+548×361)/(362×548-186)2.(1988+1989×1987)/(1988×
1.(362+548×361)/(362×548-186)
= (362+548×361)/(361×548+548-186)
= (362+548×361)/(361×548+362)
= 1
2.(1988+1989×1987)/(1988×1989-1)
= (1988+1989×1987)/(1987×1989+1989-1)
= (1988+1989×1987)/(1987×1989+1988)
= 1
3.(204+584×1991)/(1992×584―380)―1/143
=(204+584×1991)/(1991×584+584―380)―1/143
= (204+584×1991)/(1991×584+204)―1/143
= 1―1/143
= 142/143