计算：1、29/30+41/42+55/56+71/72+89/90+109/110
=1-1/30+1-1/42+1-1/56+1-1/72+1-/90+1-/110
=6-(1/30+1/42+1/56+1/72+1/90+1/110)
=6-［(14/420+10/420)+(9/504+7/504)+(11/990+9/990)］
=6-(2/35+2/63+10/99)
=6-(4/45+10/99)
=6-(44/495+50/495)
=6-94/495
=5右401/495
2、23又5/6-11又7/12+19又9/20-7又11/30+5又13/42-3又15/56+1又17/72
=23+5/6-(11+7/12)+19+9/20-(7+11/30)+5+13/42-(3+15/56)+1+17/72
=23+5/6-11-7/12+19+9/20-7-11/30+5+13/42-3-15/56+1+17/72
=(23-11+19-7+5-3+1)+(5/6-7/12)+(9/20-11/30)+(13/42-15/56)+17/72
=27+1/4+1/12+1/24+17/72
=27+(18+6+3+17)/72
=27+44/72
=27+11/18
=27右11/18