Bài 5:
a,1111+1212+1313+1414+1515+1616/2020+2121+2222+2323+2424+2525
b,5.4:0,4x1420+4,5x780x3/3+6+9+12+.....+24+27
c,7,2:2x28,6+1,43x2x64/2+2+4+6+10+16+...110
1111+1212+1313+1414+1515+1616 / 2020+2121+2222+2323+2424+2525 =?
\(\frac{2323+1313+1414+1515+1616}{4141+2222+2323+2424+2525}\)
=\(\frac{8181}{13635}\)
1010 + 1111 +1212 + 1313 +1414 + 1515
2020 + 2121 + 2222 + 2323 + 2424 + 2525
\(\frac{1010+1111+1212+1313+1414+1515}{2020+2121+2222+2323+2424+2525}=\frac{10\times101+11\times101+12\times101+13\times101+14\times101+15\times101}{20\times101+21\times101+22\times101+23\times101+24\times101+25\times101}=\frac{101\times\left(10+11+12+13+14+15\right)}{101\times\left(20+21+22+23+24+25\right)}\)
\(=\frac{10+11+12+13+14+15}{20+21+22+23+24+25}=\frac{75}{135}=\frac{5}{9}\)
1010+1111+1212+1313+1414+1515= 7575
2020+2121+2222+2323+2424+2525= 13635
bài 1: Tính biểu thức 1 cách hợp lý\(\frac{1010+1111+1212+1313+1414+1515+1616+1717}{2020+2121+2222+2323+2424+2525+2626+2727}\)
bài 2: Tím y là số tự nhiên
\(2< \)( \(\frac{1}{6}+\frac{2}{15}+\frac{3}{40}+\frac{4}{96}\)):5 x y \(< \frac{5}{6}\)
\(\frac{1010+1111+1212+1313+1414+1515+1616+1717}{2020+2121+2222+2323+2424+2525+2626+2727}\)
\(=\frac{101.10+101.11+...+101.17}{101.20+101.21+...+101.27}\)
\(=\frac{101.\left(10+11+...+17\right)}{101.\left(20+21+...+27\right)}\)
\(=\frac{108}{188}\)
\(=\frac{27}{47}\)
\(2>\left(\frac{1}{6}+\frac{2}{15}+\frac{3}{40}+\frac{4}{96}\right)\cdot5.y>\frac{5}{6}\)
\(\Rightarrow2>\left(\frac{1}{6}+\frac{2}{15}+\frac{3}{40}+\frac{1}{24}\right):5.y>\frac{5}{6}\)
\(\Rightarrow2>\left(\frac{20}{120}+\frac{16}{120}+\frac{9}{120}+\frac{5}{120}\right):5.y>\frac{5}{6}\)
\(\Rightarrow2>\frac{5}{12}:5.y>\frac{5}{6}\)
\(\Rightarrow2>\frac{1}{12}.y>\frac{5}{6}\)
Đặt :\(\frac{1}{12}.y=2\Rightarrow y=2:\frac{1}{12}=24\)
\(\frac{1}{12}.y=\frac{5}{6}\Rightarrow y=\frac{5}{6}:\frac{1}{12}=10\)
\(\Rightarrow24>y>10\)
\(\Rightarrow y\in\left\{11;12;...;23\right\}\)
\(\frac{1414+1515+1616+1717+1818+1919}{2020+2121+2222+2323+2424+2525}\)
\(\frac{1414+1515+1616+1717+1818+1919}{2020+2121+2222+2323+2424+2525}=\frac{9999}{13635}=\frac{11}{15}\)
tính nhanh
\(\frac{1414+1515+1616+1717+1818+1919}{2020+2121+2222+2323+2424+2525}\)
\(\frac{1414+1515+1616+1717+1818+1919}{2020+2121+2222+2323+2424+2525}\)
\(=\frac{101\times\left(14+15+16+17+18+19\right)}{101\times\left(20+21+22+23+24+25\right)}\)
\(=\frac{14+15+16+17+18+19}{20+21+22+23+24+25}\)
+) Tử số :
Số các số hạng là : ( 19 - 14 ) : 1 + 1 = 6 ( số )
Tổng là : ( 19 + 14 ) x 6 : 2 = 99
+) Mẫu số :
Số các số hạng là : ( 25 - 20 ) : 1 + 1 = 6 ( số )
Tổng là : ( 25 + 20 ) x 6 : 2 = 135
\(\Leftrightarrow\frac{99}{135}=\frac{11}{15}\)
Thực hiện phép tính:
\(\frac{1414+1515+1616+1717+1818+1919}{2020+2121+2222+2323+2424+2525}\)
\(\frac{1414+1515+1616+1717+1818+1919}{2020+2121+2222+2323+2424+2525}\)
\(=\frac{101\left(14+15+16+17+18+19\right)}{101\left(20+21+22+23+24+25\right)}\)
\(=\frac{\left(19+14\right)\left(19-14+1\right):2}{\left(25+20\right)\left(25-20+1\right):2}\)
=\(\frac{33.6:2}{45.6:2}=\frac{33}{45}=\frac{11}{15}\)
tính nhanh
\(\frac{1414+1515+1616+1717+1818+1919}{2020+2121+2222+2323+2424+2525}\)
\(\frac{1414+1515+1616+1717+1818+1919}{2020+2121+2222+2323+2424+2525}\)
= \(\frac{\left(1414+1919\right)+\left(1515+1818\right)+\left(1616+1717\right)}{\left(2020+2525\right)+\left(2121+2424\right)+\left(2222+2323\right)}\)
= \(\frac{3333+3333+3333}{4545+4545+4545}=\frac{3333}{4545}=\frac{11}{15}\)
t i c k nhé!! 45435436457
Tính nhanh:1414+1515+1616+1717+1818+1919/2020+2121+2222+2323+2424+2525
1414+1515+1616+1717+1818+1919/2020+2121+2222+2323+2424+2525=2525 nhé bạn
