\(\frac{1}{10}+\frac{4}{20}+\frac{9}{30}+.....+\frac{81}{90}\)
\(=\frac{1}{10}+\frac{2}{10}+\frac{3}{10}+...+\frac{9}{10}\)
\(=\frac{\left(9+1\right)\times\left(9+1-1\right):2}{10}\)
\(=\frac{10\times9:2}{10}\)
\(=\frac{45}{10}=4,5\)
1/10 + 4/20 + 9/30 + 16/40 + 25/50 + 36/60 + 49/70 + 64/80 + 81/90
1/10 + 4/20 + 9/30 + 16/40 + 25/50 + 36/60 + 49/70 + 64/80 + 81/90
1/10+4/20+9/30+16/40+25/50+36/60+49/70+64/80+81/90
giải giúp mình gấp cả lời giải nhé
tính bằng cách thuận tiện nhất
1/10 + 4/20+9/30+16/40+ 25/50+36/60+49/70 +64/80+81/90
1/10+4/20+9/30+16/40+25/50+36/60+49/70+64/30+81/90
Tính rồi viết kết quả dưới dạng số thập phân:
a) \(\dfrac{1}{10}\) + \(\dfrac{4}{20}\) + \(\dfrac{9}{30}\) + \(\dfrac{16}{40}\) + \(\dfrac{25}{50}\) + \(\dfrac{36}{60}\) + \(\dfrac{49}{70}\) + \(\dfrac{64}{80}\) + \(\dfrac{81}{90}\)
b) ( \(\dfrac{4}{5}\) x \(\dfrac{3}{8}\) + \(\dfrac{4}{5}\) x \(\dfrac{5}{8}\) - \(\dfrac{4}{5}\) x \(\dfrac{7}{8}\) ) : \(\dfrac{1}{2}\)
4/20+9/30+16/40+25/50+36/60+49/70+64/80
1/10+4/20+9/30+25/50+36/60+49/70+64/80+81/90
các bạn giúp mình với mai mình đi học rùi
Tính nhanh:
a,1/4+2/5+6/8+9/15+8/1
b,1/2+2/4+3/6+4/8+5/10+6/12+7/14+8/16+9/18+10/20
c,1/10+4/20+9/30+16/40+25/50+36/60+49/70+64/80+81/90
