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\(\left(a\right)37064-64\left(82+\frac{42966}{217}\right)\)
\(=37064-64\left(82+198\right)\)
\(=37064-64\cdot280\)
\(=30764-17920=19144\)
\(\left(b\right)320-\left(120,5+95,25+5,25\right)+\frac{84}{12}\cdot12,5\)
\(=320-\left(120,5+100,5\right)+7\cdot12,5\)
\(=320-221+87,5=11,5\)
\(\left(c\right)\left(4\frac{2}{5}+2\frac{3}{7}\right)-\left(2\frac{2}{5}-5\frac{4}{7}\right)\)
\(=4\frac{2}{5}-2\frac{2}{5}+2\frac{3}{7}+5\frac{4}{7}\)
\(=2+8=10\)
\(\left(d\right)\left(\frac{1998}{18}-\frac{1443}{13}\right)\left(16996-\frac{1110}{30}\cdot305\right)\)
\(=\left(111-111\right)\left(16996-\frac{1110}{30}\cdot305\right)\)
\(=0\left(16996-\frac{1110}{30}\cdot305\right)=0\)
\(\left(e\right)5\frac{3}{5}+1,75+6\frac{1}{8}+4\frac{1}{4}+3,875+3,4\)
\(=5\frac{3}{5}+1\frac{3}{4}+6\frac{1}{8}+4\frac{1}{4}+3\frac{7}{8}+3\frac{2}{5}\)
\(=5\frac{3}{5}+3\frac{2}{5}+1\frac{3}{4}+4\frac{1}{4}+6\frac{1}{8}+3\frac{7}{8}\)
\(=9+6+10=25\)
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10,6+1,75+7,625+10,25+3,875+3,4
12,35+17,875+7,275
30,225+7,275
37,5
\(5\frac{3}{5}+1,75+6\frac{1}{8}+4\frac{1}{4}+3.875+3,4\)
\(=5,6+1,75+6,125+4,25+3,875+3,4\)
\(=\left(5,6+3,4\right)+\left(1,75+4,25\right)+\left(6,125+3,875\right)\)
\(=9+6+10\)
\(=25\)
![](https://rs.olm.vn/images/avt/0.png?1311)
Nếu + 100 thì giải thế này nha :
1/2.3 + 1/3.4 + .... + 1/98.99 + 100
= (3-2)/2.3+(4-3)/3.4+.....+(99-98)/98.99 +100
= 1/2 - 1/3 + 1/3 - 1/4 + ...... + 1/98 - 1/99 + 100
= 1/2 - 1/99 + 100 = 97/198 + 100 = 19897/198
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\(=1x2x\frac{3}{2}x\frac{4}{3}x\frac{5}{4}x\frac{6}{5}x\frac{7}{6}x\frac{8}{7}\)
\(=\frac{1x2x3x4x5x6x7x8}{1x1x2x3x4x5x6x7}=8\)
\(1:\frac{1}{2}:\frac{2}{3}:\frac{3}{4}:\frac{4}{5}:\frac{5}{6}:\frac{6}{7}:\frac{7}{8}=8\)
chúc bn học gioi!
nhae$
hihiLê Thị Thu Hương
h@__@