Tính nhanh , bài nhiều TvT
1 ) ( 30 : 7\(\frac{1}{2}\)+ 0,5 . 3 - 1,5 ) . ( \(4\frac{1}{2}-\frac{9}{2}\)) : ( 14,5 . 100 )
2 ) \(\frac{1999.2001-1}{1998+1999.2000}.\frac{7}{5}\)
3 ) \(\frac{1978.1979+1980.21+1985}{1980.1979-1978.1979}\)
4 ) \(\frac{12,48:0,5.6,25.4.2}{2.3,12.1,25:0,25.10}\)
5 ) \(\frac{19,8:0,2.44,44.2.13,2:0,23}{3,3.88,88:0,5.6,6:0,125.5}\)
6 ) \(\frac{1+3+6+10+...+45+55}{1.10+2.9+3.8+...+8.3+9.2+10.1}\)
7 ) \(\frac{5}{1.5.8}+\frac{5}{5.8.12}+\frac{5}{8.12.15}+...+\frac{5}{33.36.40}\)
8 ) \(\frac{1}{4}+\frac{1}{24}+\frac{1}{124}\) \(\frac{2}{7}+\frac{2}{17}+\frac{2}{127}\)
________________________ + ____________________________ ( Đây là phân số )
\(\frac{3}{4}+\frac{3}{24}+\frac{3}{124}\) \(\frac{3}{7}+\frac{3}{17}+\frac{3}{127}\)
9 ) \(\left(1+\frac{1}{3}\right).\left(1+\frac{1}{8}\right).\left(1+\frac{1}{15}\right).\left(1+\frac{1}{24}\right).\left(1+\frac{1}{35}\right)\)
10 ) \(\frac{3}{4}.\frac{8}{9}.\frac{15}{16}.\frac{24}{25}..............\frac{9999}{10000}\)
11 ) \(\frac{1}{51}+\frac{1}{52}+...+\frac{1}{100}\)
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\(\frac{1}{1.2}+\frac{1}{3.4}+...+\frac{1}{99.100}\)
12 ) \(\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{100}\)
_________________________________________
\(\frac{1}{99}+\frac{2}{98}+\frac{3}{97}+...+\frac{98}{2}+\frac{99}{1}\)
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tớ sẽ giúp bạn giải phần 8:\
1/4 +1/24 +1/124 2 x [ 1/7 +1/17 +1/127] ______________ + _________________ =1/3 +2/3=1 3 x[1/4 +1/24 +1/124] 3 x [1/7 +1/17 +1/127]