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tính bằng cách thuận tiện nhất
3/4*4/5:3/5*6/7:1/7*5/6
các bạn giải rõ giúp mình nha
ai nhanh mình tick
3/4 x 4/5 : 3/5 x 6/7 : 1/7 x 5/6
= 3/4 x 4/5 x 5/3 x 6/7 x7/1 x 5/6
= 5
\(\frac{1.3.5+2.6.10+4.12.20+7.21.35}{1.5.7+2.10.14+4.20.28+7.35.49}\)
\(=\frac{1.3.5\left(1+2+4+7\right)}{1.5.7\left(1+2+7+7\right)}=\frac{1.3.5}{1.5.7}=\frac{15}{35}=\frac{3}{7}\)
\(\frac{1\cdot3\cdot5+2\cdot6\cdot10+4\cdot12\cdot20+7\cdot21\cdot35}{1\cdot5\cdot7+2\cdot10\cdot14+4\cdot20\cdot28+7\cdot35\cdot49}\)
\(=\)\(\frac{1\cdot3\cdot5\cdot\left(1+2+4+7\right)}{1\cdot5\cdot7\cdot\left(1+2+7+7\right)}\)
\(=\frac{1\cdot3\cdot5}{1\cdot5\cdot7}\)\(=\frac{15}{35}=\frac{3}{7}\)
bn vội quá viết nhầm lun kìa
hj hj chúc bn làm bài tốt nha
3/10:7/6:3/7
=3/10x6/7:3/7
=9/35x7/3
=3/5
nhớ k cho mk nha
chúc bạn học tốt
\(\frac{3}{10}:\frac{7}{6}:\frac{3}{7}\)
\(=\frac{3}{10}.\frac{6}{7}.\frac{7}{3}\)
\(=\frac{6}{10}\)
\(=\frac{3}{5}\)
1/10+2/20+3/30+4/40+5/50+6/60+7/70+8/80+9/90
=1/10+1/10+1/10+1/10+1/10+1/10+1/10+1/10+1/10
=1/10*9=9/10
7,15 x 10 + 7,15 x 91 - 7,15
= 7,15 x 10 + 7,15 x 91 - 7,15 x 1
= 7,15 x ( 10 + 91 - 1 )
= 7,15 x 100
= 715
Tk nha
Chúc học tốt nha bạn!!!
\(A=\frac{7}{2}.\left(\frac{2}{1.3}+\frac{2}{3.5}+.......+\frac{2}{99.101}\right)\)
\(=\frac{7}{2}.\left(1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+......+\frac{1}{99}-\frac{1}{101}\right)\)
\(=\frac{7}{2}.\left(1-\frac{1}{101}\right)\)
\(=\frac{7}{2}.\frac{100}{101}\)
\(=\frac{350}{101}\)
\(A=\frac{7}{2}.\left(\frac{2}{1.3}+\frac{2}{3.5}+.....+\frac{2}{99.101}\right)\)
\(=\frac{7}{2}.\left(1-\frac{1}{3}+\frac{1}{3}-.....+\frac{1}{99}-\frac{1}{101}\right)\)
\(=\frac{7}{2}.\left(1-\frac{1}{101}\right)\)
\(=\frac{7}{2}.\frac{100}{101}\)
\(=\frac{350}{101}\)
\(\frac{4}{3}:\frac{5}{4}:\frac{6}{5}:\frac{7}{6}:\frac{8}{7}:\frac{9}{8}\)
=\(\frac{4}{3}\times\frac{4}{5}\times\frac{5}{6}\times\frac{6}{7}\times\frac{7}{8}\times\frac{8}{9}\)
=\(\frac{16}{27}\)
1.
\(a,\frac{1}{7}+\frac{3}{4}+\frac{2}{7}+\frac{4}{7}=\frac{1}{7}+\frac{2}{7}+\frac{4}{7}+\frac{3}{4}\)
\(=1+\frac{3}{4}=\frac{7}{4}.\)
\(b,\frac{4}{7}:\frac{2}{5}+\frac{3}{7}:\frac{2}{5}-\frac{7}{9}=\left(\frac{4}{7}+\frac{3}{7}\right):\frac{2}{5}-\frac{7}{9}\)
\(=1:\frac{2}{5}-\frac{7}{9}=\frac{5}{2}-\frac{7}{9}\)
\(=\frac{31}{18}.\)
a)3/4+(1/7+2/7+4/7)
=3/4+1
=7/4
b)2/5:(4/7+3/7)-7/9
=2/5:1-7/9
=2/5-7/9
=-17/45
\(\frac{3}{10}:\frac{7}{6}:\frac{3}{7}\)
\(=\frac{3}{10}\times\frac{6}{7}\times\frac{7}{3}\)
\(=\frac{3}{5}\)
Hok Tốt!!!
\(\frac{3}{10}:\frac{7}{6}:\frac{3}{7}\)
\(=\left(\frac{3}{10}:\frac{3}{7}\right):\frac{7}{6}\)
\(=\frac{7}{10}:\frac{7}{6}\)
\(=\frac{3}{5}\)