Tính bằng cách thuận tiện nhất:
\(\frac{1}{10}+\frac{2}{20}+\frac{3}{30}+\frac{4}{40}+\frac{5}{50}+\frac{6}{60}+\frac{7}{70}+\frac{8}{80}+\frac{9}{90}\)
tính bằng cách thuận tiện
\(\frac{1}{10}+\frac{2}{20}+\frac{3}{30}+\frac{4}{40}+\frac{5}{50}+\frac{6}{60}+\frac{7}{70}+\frac{8}{80}+\frac{9}{90}\)
=...........................................................................................................................
=................................................................................................................
\(=\frac{1}{10}+\)\(\frac{1}{10}+\)\(\frac{1}{10}+\)\(\frac{1}{10}+\)\(\frac{1}{10}+\)\(\frac{1}{10}+\)\(\frac{1}{10}+\)\(\frac{1}{10}+\)\(\frac{1}{10}\)
\(=\frac{1}{10}.9\)
\(=\frac{9}{10}\)
Đúng 100%
Đúng 100%
Đúng 100%
\(\frac{1}{10}+\frac{2}{20}+\frac{3}{30}+\frac{4}{40}+\frac{5}{50}+\frac{6}{60}+\frac{7}{70}+\frac{8}{80}+\frac{9}{90}\)
\(=\frac{1}{10}+\frac{1}{10}+\frac{1}{10}+\frac{1}{10}+\frac{1}{10}+\frac{1}{10}+\frac{1}{10}+\frac{1}{10}+\frac{1}{10}\)
\(=\frac{1}{10}\times9\)
\(=\frac{9}{10}\)
tính bằng cách thuận tiện nhất:
\(\frac{1}{10}\)+\(\frac{2}{20}\)+\(\frac{3}{30}\)+\(\frac{4}{40}\)+\(\frac{5}{50}\)+\(\frac{6}{60}\)+\(\frac{7}{70}\)+\(\frac{8}{80}\)+\(\frac{9}{90}\)
GIÚP MK NHANH VỚI,THANKS TRƯỚC
Tính giá trị biểu thức
\(\frac{1}{10}+\frac{2}{20}+\frac{9}{30}+\frac{16}{40}+\frac{25}{50}+\frac{36}{60}+\frac{49}{70}+\frac{69}{80}+\frac{81}{90}\)
=1/10+1/10+3/10+4/10+5/10+6/10+7/10+8/10+9/10
=1/10+45/10
=46/10=23/5
tính bằng cách thuận tiện nhất: \(6\frac{2}{7}+7\frac{3}{5}+8\frac{6}{9}+9\frac{1}{4}+\frac{2}{5}+\frac{5}{7}+\frac{1}{3}+\frac{3}{4}\)
Giúp tôi giải toán:
\(\frac{1}{10}+\frac{4}{20}+\frac{9}{30}+\frac{16}{40}+\frac{25}{50}+\frac{36}{60}+\frac{49}{70}+\frac{64}{80}+\frac{81}{90}\)
1/10+4/20+9/30+16/40+25/50+36/60+49/70+64/80+81/90
=1/10+2/10+3/10+4/10+5/10+6/10+7/10+8/10+9/10
=1+2+3+4+5+6+7+8+9/10
=45/10 (tự rút gọn)
Rút gọn các phân số ta có :
1/10 + 2/10 + 3/10 + 4/10 + 5/10 + 6/10 + 7/10 + 8/10 + 9/10
= ( 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 ) / 10
= 45/10 = 4,5
Tìm x biết: \(\frac{x+10}{90}+\frac{x+20}{80}+\frac{x+30}{70}+\frac{x+40}{60}+\frac{x+50}{50}=-5\)
\(\frac{x+10}{90}+\frac{x+20}{80}+\frac{x+30}{70}+\frac{x+40}{60}+\frac{x+50}{50}=-5\)
<=> \(\frac{x+10}{90}+1+\frac{x+20}{80}+1+\frac{x+30}{70}+1+\frac{x+40}{60}+1+\frac{x+50}{50}+1=0\)
<=> \(\frac{x+100}{90}+\frac{x+100}{80}+\frac{x+100}{70}+\frac{x+100}{60}+\frac{x+100}{50}=0\)
<=> \(\left(x+100\right)\left(\frac{1}{90}+\frac{1}{80}+\frac{1}{70}+\frac{1}{60}+\frac{1}{50}\right)=0\)
<=> x + 100 = 0
<=> x = -100
Vậy x = -100
Tính nhanh giá trị biểu thức sau:\(\frac{4}{20}+\frac{9}{30}+\frac{16}{40}+\frac{25}{50}+\frac{36}{60}+\frac{49}{70}+\frac{64}{80}+\frac{81}{90}+\frac{100}{100}+\frac{121}{110}+\frac{144}{120}+\frac{169}{130}\)
=2/10+3/10+4/10+......+13/10
=\(\frac{2+3+4+......+13}{10}\)
=90/10=9
k cho mình nha
tính:
a)
\(\frac{1}{10}+\frac{4}{20}+\frac{9}{30}+\frac{25}{50}+\frac{36}{60}+\frac{64}{80}+\frac{49}{70}+\frac{81}{90}\)
b)
\(\frac{2}{3\times5}+\frac{2}{5\times7}+\frac{2}{7\times9}+\frac{2}{9\times11}+...+\frac{2}{97\times99}\)
Ai làm nhanh mk cho 3 tik nha!
Tìm x biết: \(\frac{x+10}{90}+\frac{x+20}{80}+\frac{x+30}{70}+\frac{x+40}{60}+\frac{x+50}{50}\)