1加3又6分之1加5又12分之1加7有20分之1加9又30分之1加11又42分之一加13又56分之1加15又72分之1
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1+3又6分之1+5又12分之1+7又20分之1+9又30分之1+11又42分之1+13又56分之1+15又72分之1
=1+3+1/6+5+1/12+7+1/20+9+1/30+11+1/42+13+1/56+15+1/72
=(1+3+5+7+9+11+13+15)+(1/6+1/12+1/20+1/30+1/42+1/56+1/72)
=64+1/(2×3)+1/(3×4)+1/(4×5)+1/(5×6)+1/(6×7)+1/(7×8)+1/(8×9)
=64+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+1/7-1/8+1/8-1/9
=64+1/2-1/9
=64+9/18-2/18
=64+7/18
=64又18分之7
=1+3+1/6+5+1/12+7+1/20+9+1/30+11+1/42+13+1/56+15+1/72
=(1+3+5+7+9+11+13+15)+(1/6+1/12+1/20+1/30+1/42+1/56+1/72)
=64+1/(2×3)+1/(3×4)+1/(4×5)+1/(5×6)+1/(6×7)+1/(7×8)+1/(8×9)
=64+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+1/7-1/8+1/8-1/9
=64+1/2-1/9
=64+9/18-2/18
=64+7/18
=64又18分之7
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