\(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+\frac{1}{5.6}+\frac{1}{6.7}+\frac{1}{7.8}+\frac{1}{8.9}\)
\(=\frac{1}{1}+\frac{1}{2}-\frac{1}{3}+\frac{1}{4}-..........-\frac{1}{8}+\frac{1}{9}\)
\(=\frac{1}{1}-\frac{1}{9}\)
\(=\frac{8}{9}\)
Mình giải đúng đó
1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72=????
1/90-1/72-1/56-1/42-1/30-1/20-1/12-1/6-1/2
1/2 + 1/6 + 1/12 + 1/20 + 1/30 + 1/42 + 1/56 + 1/72 + 1/90
1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90+1/10
1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90
cac ban giup mik voi
1/2+1/6+1/12+1/20+1/30+1/42+1/56 +1/72+1/90+? các bạn gi cách giải cho mình nhé.mình k cho
Tính nhanh:
1/6 + 1/12 + 1/20 + 1/30 + 1/42 + 1/56 + 1/72 + 1/90
Mình ko hiểu mong mọi người giúp
a ) 12,8 x 195 + 12,8 x 804 + 12,8
b) 1/2 +1/6 + 1/12+ 1/20+ 1/30 +1/42 +1/56 +1/72+ 1/90
tính nhanh
1/6 + 1/12 + 1/20 + 1/30 + 1/42 + 1/56 + 1/72 + 1/90