Question

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口算： 1÷9+4/9= 7-1/7= 6/5-1/6= 1+1/6= 2-9/17=

能简算的要简算
①13/18×5.16+百分之516×5/18
②2008×2008/2009
③1/8×百分之25÷百分之25

Answer 1

1÷9+4/9=5/9 7-1/7=48/7 6/5-1/6=31/30 1+1/6=7/6 2-9/17=25/17
①13/18×5.16+516%×5/18
=13/18×5.16+5.16×5/18
=5.16×（13/18+5/18）
=5.16×1
=5.16
②2008×2008/2009
=2008×[(2009-1)/2009]
=2008×(2009/2009-1/2009)
=2008×1-2008×1/2009
=2008-2008/2009
=4032064/2009
③1/8×25%÷25%
=1/8×1/4×4
=1/8×1
=1/8

Answer 2

1÷9+4/9= 5/9 7-1/7=（7 * 7 -1）/ 7= 48 / 7 6/5-1/6= ( 6*6-1*5)/(5*6)=(36-5)/30=31/30
1+1/6= 6/6+1/6=(6+1)/6=7/6 2-9/17= 2*17/17 - 9/17=34/17-9/17=(34-9)/17=25/7