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\(\frac{1}{2}:0,5-\frac{1}{4}:0,25+\frac{1}{8};0,125-\frac{1}{10}:0,1=\frac{1}{2}:\frac{1}{2}-\frac{1}{4}:\frac{1}{4}+\frac{1}{8}:\frac{1}{8}-\frac{1}{10}:\frac{1}{10}=1-1+1-1=0+0=0\)
em ơi cái này = 0 . Anh chắc chắn vs em 100000000000000000000000000000000000000000000000000000000000000000%
Anh lớp 7 mà
a) 5/30+15/90+25/150+35/210+45/270
=1/6+1/6+1/6+1/6+1/6
=1/6 x 5
=5/6
b) 1/2+1/6+1/12+1/20+....+1/56
=1/1x2+1/2x3+1/3x4+1/4x5+.....1/7x8
=1/1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+.......-1/7+1/7-1/8
=1/1-1/8
=7/8
c) mình chịu
\(S=\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+\frac{1}{30}+\frac{1}{90}+\frac{1}{100}\)
\(S=\left(\frac{1}{6}+\frac{1}{12}\right)+\left(\frac{1}{20}+\frac{1}{100}\right)+\left(\frac{1}{30}+\frac{1}{90}\right)\)
\(S=\left(\frac{2}{12}+\frac{1}{12}\right)+\left(\frac{5}{100}+\frac{1}{100}\right)+\left(\frac{3}{90}+\frac{1}{90}\right)\)
\(S=\frac{3}{12}+\frac{6}{100}+\frac{4}{90}\)
\(S=\frac{1}{4}+\frac{3}{50}+\frac{2}{45}\)
\(S=\frac{319}{900}\)
S=\(\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+\frac{1}{5.6}+\frac{1}{6.15}+..\)
\(S=SAI\)
HÌNH NHƯ SAI RỒI
HÌNH NHỨIA
Chỗ cuối mk nhầm, sửa lại nha :
\(\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+\frac{1}{30}+...+\frac{1}{90}+\frac{1}{100}\)
\(=\frac{1}{2\times3}+\frac{1}{3\times4}+\frac{1}{4\times5}+\frac{1}{5\times6}+...+\frac{1}{9\times10}+\frac{1}{100}\)
\(=\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}+...+\frac{1}{9}-\frac{1}{10}+\frac{1}{100}\)
\(=\frac{1}{2}-\frac{1}{10}+\frac{1}{100}\)
\(=\frac{50}{100}-\frac{10}{100}+\frac{1}{100}\)
\(=\frac{41}{100}\)
\(\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+\frac{1}{30}+...+\frac{1}{90}+\frac{1}{100}\)
\(=\frac{1}{2\times3}+\frac{1}{3\times4}+\frac{1}{4\times5}+\frac{1}{5\times6}+...+\frac{1}{9\times10}+\frac{1}{100}\)
\(=\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}+...+\frac{1}{9}-\frac{1}{10}+\frac{1}{100}\)
\(=\frac{1}{2}-\frac{1}{10}+\frac{1}{100}\)
\(=\frac{50}{100}-\frac{10}{100}-\frac{1}{100}\)
\(=\frac{39}{100}\)
Đúng thì k nha bn !!!!
\(\frac{1}{2}+\frac{1}{6}+...+\frac{1}{90}=\frac{1}{1\cdot2}+\frac{1}{2\cdot3}+...+\frac{1}{9\cdot10}\)
\(=\frac{1}{1}-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+...+\frac{1}{9}-\frac{1}{10}\)
\(=\frac{1}{1}-\frac{1}{10}=1-\frac{1}{10}=\frac{9}{10}\)
\(=\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+\frac{1}{5.6}+\frac{1}{6.7}+\frac{1}{7.8}+\frac{1}{8.9}+\frac{1}{9.10}\)
\(=\frac{1}{1}-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{4}-\frac{1}{5}+\frac{1}{6}-\frac{1}{7}+\frac{1}{8}-\frac{1}{9}+\frac{1}{9}-\frac{1}{10}\)
\(=\frac{1}{1}-\frac{1}{10}=\frac{9}{10}\)