答:
1.8/25*4/3=32/75
2.7/25*5=7/5
3.100*3/5=60
拓展题
将式子+1/2,再减去1/2
1/2*3+1/3*4+1/4*5+1/5*6+1/6*7+1/7*8+1/8*9+1/9*10=?
1/2+1/2*3+1/3*4+1/4*5+1/5*6+1/6*7+1/7*8+1/8*9+1/9*10-1/2
=1-1/2+1/2-1/3-1/3-1/4+1/4-1/5+1/5-1/6+/16-1/7+1/7-1/8+1/8-1/9+1/9-1/10-1/2
=1-1/10-1/2
=9/10-1/2
=2/5
1、8/25*3/4=6/25
2、100*3/5=60
拓展:(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)+(1/9-1/10)=1/2-1/10=4/10=0.4
1.6/25
2.7/5
3.60
4.2/5
1 6/25
60
2 0.4
2 7/5