tính nhanh 5/2+5/6+5/18+5/54+5/162+5/486 trình bày bài giải
Tính nhanh:
C = 5/2 + 5/6 + 5/18 + 5/54 + 5/162 + 5/486
C=5/2+5/6+5/18+5/54+5/162+5/486
C=1215/486+405/486+135/486+45/486+15/486+5/486
C=1215+405+135+45+15+5/486
C=1820/486=910/243
tính nhanh :
5/2+5/6+5/18+5/54+5/162+5/486=?
5/2+5/6+5/18+5/54+5/162+5/486+5/1458
Giải ra cho mình nhé
bài 6 : NÂNG CAO LỚP 5 TÍNH NHANH
a= 1/2=1/6+1/18+1/54+1/162+1/486
5/2+5/6+5/18+5/54+5/162+5/486
đáp án :910/243
Hok tốt
Tính nhanh:
bai 1:A=1/5+1/10+1/20+1/40+....+1/1280
bai2:A=5/2+5/6+5/18+5/54+5/162+5/486+5/1458
bài 3 :A=3/2+3/8+3/32+3/128+3/512
bài 4:A=3+3/5+3/25+3/125+3/625
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B=5/2+5/6+5/18+5/54+5/162+5/486
tinh nhanh
\(\frac{5}{2}+\frac{5}{6}+\frac{5}{18}+\frac{5}{54}+\frac{5}{162}+\frac{5}{486}\)
\(=\frac{910}{243}NHA\) Nguyễn Thị Hà My !
Tính GTBT: A= 5/2+ 5/6+5/18+ 5/54+5/162+5/486
\(\dfrac{5}{2}+\dfrac{5}{6}+\dfrac{5}{18}+\dfrac{5}{54}+\dfrac{5}{162}+\dfrac{5}{486}\)
\(=\dfrac{5.243}{486}+\dfrac{5.81}{486}+\dfrac{5.27}{486}+\dfrac{5.9}{486}+\dfrac{5.3}{486}+\dfrac{5}{486}\)
\(=\dfrac{1215+405+135+45+15+5}{486}\)
\(=\dfrac{1820}{486}=\dfrac{910}{243}\)