1/3+3/4+2/5+5/7+7/8+9/20+10/21+11/24+19/35=91/20
[(5又1/4-4.25)×5/8]÷3/8+3.3÷1又5/6 =52/15
题1 其实是个求最小公倍数的题
1/3+3/4+2/5+5/7+7/8+9/20+10/21+11/24+19/35
=(1/3+3/4+7/8+11/24)+(2/5+9/20)+(5/7+10/21+19/35)
=(8/24+18/24+21/24+11/24)+(8/20+9/20)+(75/105+50/105+57/105)
=29/12+17/20+26/15
=145/60+51/60+104/60
=300/60
=5
题2
[(5+1/4-4.25)X5/8]÷3/8+3.3÷(11/6)
=1X(5/8)X(8/3)+(33/10)X(6/11)
=5/3+9/5
=25/15+27/15
=14/5
1/3+3/4+2/5+5/7+7/8+9/20+10/21+11/24+19/35
=(1/3+3/4+7/8+11/24)+(2/5+9/20)+(5/7+10/21+19/35)
=(8/24+18/24+21/24+11/24)+(8/20+9/20)+(75/105+50/105+57/105)
=29/12+17/20+26/15
=145/60+51/60+104/60
=300/60
=5
[(5+1/4-4.25)X5/8]]÷3/8+3.3÷(11/6)
=1X(5/8)X(8/3)+(33/10)X(6/11)
=5/3+9/5
15/62