1+2+3+4+5+6+7+8+9+10
=(1+10)+(2+9)+(3+8)+(4+7)+(5+6)
=11+11+11+11+11
=11x5
=55
#)Giải :
\(\frac{1}{11}+\frac{2}{11}+\frac{3}{11}+\frac{4}{11}+\frac{5}{11}+\frac{6}{11}+\frac{7}{11}+\frac{8}{11}+\frac{9}{11}+\frac{10}{11}\)
\(=\left(\frac{1}{11}+\frac{10}{11}\right)+\left(\frac{2}{11}+\frac{9}{11}\right)+\left(\frac{3}{11}+\frac{8}{11}\right)+\left(\frac{4}{11}+\frac{7}{11}\right)+\left(\frac{5}{11}+\frac{6}{11}\right)\)
\(=1+1+1+1+1\)
\(=5\)
#~Will~be~Pens~#
1/11 + 2/11 + 3/11 + 4/11 + 5/11 + 6/11 + 7/11 + 8/11 + 9/11 + 10/11
= ( 1/11 + 10/11 ) + ( 2/11 + 9/11 ) + ( 3/11 + 8/11 ) + ( 4/11 + 7/11 ) + ( 5/11 + 6/11 )
= 1 + 1 + 1 + 1 + 1
= 1 . 5
= 5
#Tề _ Thiên
\(\frac{1}{11}+\frac{2}{11}+\frac{3}{11}+\frac{4}{11}+\frac{5}{11}+\frac{6}{11}+\frac{7}{11}+\frac{8}{11}+\frac{9}{11}+\frac{10}{11}\)
\(=\left(\frac{1}{11}+\frac{10}{11}\right)+\left(\frac{2}{11}+\frac{9}{11}\right)+\left(\frac{3}{11}+\frac{8}{11}\right)+\left(\frac{4}{11}+\frac{7}{11}\right)+\left(\frac{5}{11}+\frac{6}{11}\right)\)
\(=1+1+1+1+1\)
\(=1\times5\)
\(=5\)
~ Hok tốt ~
\(\frac{1}{11}+\frac{2}{11}+\frac{3}{11}+\frac{4}{11}+\frac{5}{11}+\frac{6}{11}+\frac{7}{11}+\frac{8}{11}+\frac{9}{11}+\frac{10}{11}\)
\(=\left(\frac{1}{11}+\frac{10}{11}\right)+\left(\frac{2}{11}+\frac{9}{11}\right)+\left(\frac{3}{11}+\frac{8}{11}\right)+\left(\frac{4}{11}+\frac{7}{11}\right)+\left(\frac{5}{11}+\frac{6}{11}\right)\)
\(=1+1+1+1+1\)
\(=5\)
\(\frac{1}{11}+\frac{2}{11}+\frac{3}{11}+\frac{4}{11}+\frac{5}{11}+\frac{6}{11}+\frac{7}{11}+\frac{8}{11}+\frac{9}{11}+\frac{10}{11}\)
\(=\left(\frac{1}{11}+\frac{10}{11}\right)+\left(\frac{2}{11}+\frac{9}{11}\right)+\left(\frac{3}{11}+\frac{8}{11}\right)+\left(\frac{4}{11}+\frac{7}{11}\right)+\left(\frac{5}{11}+\frac{6}{11}\right)\)
\(=1+1+1+1+1\)
\(=5\)
Bài làm:
Ta có:
\(\frac{1}{11}+\frac{2}{11}+\frac{3}{11}+\frac{4}{11}+\frac{5}{11}+\frac{6}{11}+\frac{7}{11}+\frac{8}{11}+\frac{9}{11}+\frac{10}{11}\)
\(=\left(\frac{1}{11}+\frac{10}{11}\right)+\left(\frac{2}{11}+\frac{9}{11}\right)+\left(\frac{3}{11}+\frac{8}{11}\right)+\left(\frac{4}{11}+\frac{7}{11}\right)+\left(\frac{5}{11}+\frac{6}{11}\right)\)
\(=1+1+1+1+1=1\times5=5\)
#Mạt Mạt#