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\(a,\dfrac{13}{19}+\dfrac{18}{19}+\dfrac{17}{19}=\dfrac{13+18+17}{19}=\dfrac{48}{19}\\ b,\dfrac{3}{5}+\dfrac{3}{16}+\dfrac{13}{16}=\dfrac{3}{5}+\left(\dfrac{3}{16}+\dfrac{13}{16}\right)=\dfrac{3}{5}+\dfrac{16}{16}=\dfrac{3}{5}+1=\dfrac{3}{5}+\dfrac{5}{5}=\dfrac{8}{5}\)
\(a\dfrac{13+18+17}{19}=\dfrac{48}{19}\)
\(b\dfrac{3}{5}+\dfrac{3+13}{16}=\dfrac{3}{5}+1=\dfrac{3}{5}+\dfrac{5}{5}=\dfrac{8}{5}\)
a, \(\frac{5}{11}\times\frac{7}{25}+\frac{15}{11}\times\frac{1}{5}\)
\(=\frac{5}{11}\times\frac{7}{25}+\frac{5}{11}\times\frac{3}{5}\)
\(=\frac{5}{11}\times\left(\frac{7}{25}+\frac{3}{5}\right)\)
\(=\frac{5}{11}\times\frac{22}{25}\)
\(=\frac{2}{5}\)
b, \(\frac{3}{7}\times\frac{25}{19}-\frac{1}{7}\times\frac{18}{19}\)
\(=\frac{1}{7}\times\frac{75}{19}-\frac{1}{7}\times\frac{18}{19}\)
\(=\frac{1}{7}\times\left(\frac{75}{19}-\frac{18}{19}\right)\)
\(=\frac{1}{7}\times3\)
\(=\frac{3}{7}\)
C1) 17/25.13/19+17/25.6/19 C2) 17/25.13/19+17/25.6/19
=17/25.(13/19+6/19) =221/475+102/475
=17/25.1=17/25 =17/25
Học tốt nha
\(C1:\)
\(\frac{17}{25}x\frac{13}{19}+\frac{17}{25}x\frac{6}{19}\)
\(=\frac{17}{25}x\left(\frac{13}{19}+\frac{6}{19}\right)\)
\(=\frac{17}{25}x1\)
\(=\frac{17}{25}\)
\(C2:\)
\(\frac{17}{25}x\frac{13}{19}+\frac{17}{25}x\frac{6}{19}\)
\(=\frac{221}{475}+\frac{102}{475}\)
\(=\frac{323}{475}=\frac{17}{25}\)
a, \(\frac{6}{7}.\frac{16}{15}.\frac{7}{6}.\frac{21}{32}=\frac{6}{7}.\frac{7}{6}.\frac{16}{15}.\frac{21}{32}\)=\(1.\frac{16}{15}.\frac{21}{32}=\frac{7}{5.2}=\frac{7}{10}\)
Phần b T2
c,\(\frac{7}{4}.\frac{11}{21}+\frac{11}{21}.\frac{5}{4}=\frac{11}{21}.\left(\frac{7}{4}+\frac{5}{4}\right)\)=\(\frac{11}{21}.3=\frac{11}{7}\)
(20+10)-(11+19)+(12+18)-(13+17)+(14+16)-15
=30-30+30-30-15+30
=15
10-11+12-13+14-15+16-17+18-19+20
= (10+20)+(-11-19)+(12+18)+(-13-17)+(14+16)-15
= 30-30+30-30+30-15
= 15
\(a,\frac{2}{5}+\frac{1}{6}+\frac{3}{5}\)
\(=\left(\frac{2}{5}+\frac{3}{5}\right)+\frac{1}{6}\)
\(=1+\frac{1}{6}\)
\(=\frac{7}{6}\)
Hok tốt!~
a) \(\frac{13}{19}+\frac{18}{19}+\frac{19}{19}=\left(\frac{13}{19}+\frac{17}{19}\right)+\frac{18}{19}=\frac{20}{19}+\frac{18}{19}=\frac{48}{19}\)
b) \(\frac{3}{5}+\frac{3}{16}+\frac{13}{16}=\left(\frac{3}{16}+\frac{13}{16}\right)+\frac{3}{5}=1+\frac{3}{5}=\frac{5}{5}+\frac{3}{5}=\frac{8}{5}\)
a) \(\frac{13}{19}+\frac{18}{19}+\frac{17}{19}\)
= \(\frac{31}{19}+\frac{17}{19}\)
= \(\frac{48}{19}.\)
b) \(\frac{3}{5}+\frac{3}{16}+\frac{13}{16}\)
= \(\frac{3}{5}+\left(\frac{3}{16}+\frac{13}{16}\right)\)
= \(\frac{3}{5}+\frac{16}{16}\)
= \(\frac{3}{5}+1\)
= \(\frac{3}{5}.\)