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\(a,16,88+9,76+3,12-5,13\)
\(=\left(16,88+3,12\right)+\left(9,76-5,13\right)\)
\(=20+4,63\)
\(=24,63\)
\(b,\frac{19}{11}+\frac{8}{13}+\frac{3}{11}\)
\(=\left(\frac{19}{11}+\frac{3}{11}\right)+\frac{8}{13}\)
\(=2+\frac{8}{13}\)
\(=\frac{34}{13}\)
\(c,\frac{1}{2}\div\frac{1}{4}-\frac{1}{6}\)
\(=2-\frac{1}{6}\)
\(=\frac{11}{6}\)
\(\frac{19}{35}+\frac{15}{19}+\frac{16}{35}+\frac{23}{19}+\frac{4}{15}+\frac{11}{15}\)
\(=\left(\frac{19}{35}+\frac{16}{35}\right)+\left(\frac{15}{19}+\frac{23}{19}\right)+\left(\frac{4}{15}+\frac{11}{15}\right)\)
\(=\frac{35}{35}+\frac{38}{19}+\frac{15}{15}\)
\(=1+2+1\)
\(=4\)
\(\frac{19}{35}+\frac{15}{19}+\frac{16}{35}+\frac{23}{19}+\frac{4}{15}+\frac{11}{15}\)
\(=\left(\frac{19}{35}+\frac{16}{35}\right)+\left(\frac{15}{19}+\frac{23}{19}\right)+\left(\frac{4}{15}+\frac{11}{15}\right)\)
\(=1+2+1\)
\(=4\)
Học tốt
a) \(\frac{3}{5}+\frac{6}{11}+\frac{7}{13}+\frac{5}{11}+\frac{2}{5}+\frac{19}{13}=\left(\frac{3}{5}+\frac{2}{5}\right)+\left(\frac{6}{11}+\frac{5}{11}\right)+\left(\frac{7}{13}+\frac{19}{13}\right)=1+1+2=4\)
b) \(\frac{6}{5}\times\frac{3}{8}+\frac{5}{8}\times\frac{6}{5}-\frac{4}{5}=\frac{6}{5}\times\left(\frac{3}{8}+\frac{5}{8}\right)-\frac{4}{5}=\frac{6}{5}-\frac{4}{5}=\frac{2}{5}\)
c) \(\frac{4\times5\times6\times7\times8}{8\times10\times12\times14\times16}=\frac{1}{2\times2\times2\times2\times2}=\frac{1}{32}\)
a, \(\frac{3}{5}+\frac{6}{11}+\frac{7}{13}+\frac{6}{11}+\frac{2}{5}+\frac{19}{13}\)
\(=\left(\frac{3}{5}+\frac{2}{5}\right)+\left(\frac{7}{13}+\frac{19}{13}\right)+\left(\frac{6}{11}+\frac{6}{11}\right)\)
\(=1+2+\frac{12}{11}\)
\(=3+\frac{12}{11}\)
\(=\frac{45}{11}\)
\(\frac{5}{6}+\frac{11}{12}+\frac{19}{20}+\frac{29}{30}+\frac{41}{42}+\frac{55}{56}+\frac{71}{72}+\frac{89}{90}\)
\(=1-\frac{1}{6}+1-\frac{1}{12}+1-\frac{1}{20}+1-\frac{1}{30}+1-\frac{1}{42}+1-\frac{1}{56}+1-\frac{1}{72}+1-\frac{1}{90}\)
\(=8-\left(\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+\frac{1}{30}+\frac{1}{42}+\frac{1}{56}+\frac{1}{72}+\frac{1}{90}\right)\)
\(=8-\left(\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+\frac{!}{5.6}+\frac{1}{6.7}+\frac{1}{7.8}+\frac{1}{8.9}+\frac{1}{9.10}\right)\)
\(=8-\left(\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+.....+\frac{1}{8}-\frac{1}{9}+\frac{1}{9}-\frac{1}{10}\right)\)
\(=8-\left(\frac{1}{2}-\frac{1}{10}\right)\)
\(=8-\frac{2}{5}=\frac{38}{5}\)
1/2+5/6+11/12+19/20+29/30+41/42+55/56+71/72+89/90
=1-1/2+1-1/6+1-1/12+1-1/20+1-1/30+1-1/42+1-1/56+1-1/72+1-1/90
=9 – (1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90)
=9 – [1/(1x2)+1/(2x3)+1/(3x4)+1/(4x5)+1/(5x6)+1/(6x7)+1/(7x8)+1/(8x9)+1/(9x10)]
=9 – ( 1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+1/7-1/8+1/8-1/9+1/9-1/10)
=9 – (1 – 1/10) = 9 – 9/10
= 81/10
8/19 × 5/11 + 8/19 × 6/11 + 11/19
= 8/19 × (5/11 + 6/11) + 11/19
= 8/19 × 1 + 11/19
= 8/19 + 11/19
= 1
Ủng hộ mk nha ♡_♡