tính giá trị biểu thức : A =1717/1919 * 303/1818 + 1717/1919 * 1515/1818
1717\1919×303\1818+1717\1919×1515\1818
tính nhanh \(A=\frac{1717}{1919}\times\frac{303}{1818}+\frac{17}{19}\times\frac{1515}{1818}\)
\(A=\frac{17}{19}x\frac{1}{6}+\frac{17}{19}x\frac{5}{6}\)
\(=\frac{17}{19}x\left(\frac{1}{6}+\frac{5}{6}\right)=\frac{17}{19}x1=\frac{17}{19}\)
A= \(\frac{1717}{1919}\text{ *}\frac{303}{1818}+\frac{17}{19}\text{ *}\frac{1515}{1818}\)
A= \(\frac{17}{19}\text{ *}\frac{3}{18}+\frac{17}{19}\text{ *}\frac{15}{18}\)
A= \(\frac{17}{19}\text{ *}\left(\frac{3}{18}+\frac{15}{18}\right)\)
A= \(\frac{17}{19}\text{ *}1\)
A= \(\frac{17}{19}\)
Vậy A= \(\frac{17}{19}\)
vVv Học tốt nhé bạn, mình sẽ rất vui nếu bạn k đúng cho mình, cảm ơn ban nhiều vVv
\(\frac{1717}{1919}x\frac{303}{1818}+\frac{17}{19}x\frac{1515}{1818}\)
= \(\frac{17}{19}x\frac{1}{6}\)+ \(\frac{17}{19}x\frac{5}{6}\)
= \(\frac{17}{19}\)x ( \(\frac{1}{6}+\frac{5}{6}\))
= \(\frac{17}{19}x1\)
= \(\frac{17}{19}\)
1/3 + 13/15 + 33/35 + 61/63 + 97/99
1717/1919*303/1818+17/19*1515/1818
tính nhanh H = 1414 + 1515 + 1616 + 1717 + 1818 + 1919
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
1414+1515+1616+1717+1818+1919/2020+2121+2222+2323+2424+2525
Đề bài kiểu gì vậy?VIết rõ hơn đi
1414+1515+1616+1717+1818+1919
2020+2121+2222+2323+2424+2525
So sánh: 1414+1515+1616+1717/1818+1919+2020+2121 va 2424/3636
So sánh 6262 / 7878 và 2424 / 3636
Vì 6262/7878 > 2424/3636
Nên 1414 + 1515 + 1616 + 1717 / 1818 + 1919 + 2020 + 2121 > 2424/3636
1414+1515+1616+1717+1818+1919/2020+2121+2222+2323+2424+2525
1414+1515+1616+1717+1818+1919 phần 2000+2121+2222+2323+2424+2525
\(\frac{1414+1515+1616+1717+1818+1919}{2000+2121+2222+2323+2424+2525}\)
\(=\frac{101.\left(14+15+16+17+18+19\right)}{101.\left(20+21+22+23+24+25\right)}\)
\(\frac{14+15+16+17+18+19}{20+21+22+23+24+25}=\frac{99}{135}=\frac{11}{15}\)
L_I_K_E NHA