\(\left(-3,2\right).\dfrac{15}{64}-\left(0,8-2\dfrac{4}{15}\right):3\dfrac{2}{3}\\ =-\dfrac{16}{5}.\dfrac{15}{64}-\left(\dfrac{4}{5}-\dfrac{34}{15}\right):\dfrac{11}{3}\\ =-\dfrac{3}{4}-\left(-\dfrac{22}{15}\right).\dfrac{3}{11}\\ =-\dfrac{3}{4}-\left(-\dfrac{2}{5}\right)=-\dfrac{3}{4}+\dfrac{2}{5}=-\dfrac{7}{20}\)
Hãy chọn cặp gồm hai phân số bằng nhau.
\(\dfrac{15}{-10}\) và \(\dfrac{5}{4}\)
\(\dfrac{-3}{2}\) và \(\dfrac{2}{-3}\)
\(\dfrac{2}{-3}\) và \(\dfrac{-15}{-12}\)
\(\dfrac{15}{-10}\) và \(\dfrac{-3}{2}\)
Chứng minh rằng P>3 biet P= \(\dfrac{5}{2×1}+\dfrac{4}{1×11}+\dfrac{3}{11×2}+\dfrac{1}{2×15}+\dfrac{13}{15×4}+\dfrac{15}{4×43}+\dfrac{13}{43×8}\)
Tính nhanh
\(\dfrac{3}{2^2}.\dfrac{8}{3^2}.\dfrac{15}{4^2}...\dfrac{899}{30^2}\)
1,4 . \(\dfrac{15}{49}\) - (\(\dfrac{4}{5}\) + \(\dfrac{-2}{3}\)) : \(2\dfrac{1}{5}\)
\(\dfrac{-4}{11}\times\dfrac{7}{15}-\dfrac{4}{15}\times\dfrac{8}{11}+\dfrac{-5}{11}\)
\(2\dfrac{2}{3}-2\dfrac{3}{5}\times\dfrac{10}{7}-\dfrac{7}{5}\)
các bạn làm trong hôm nay dùm mình nhé, cảm ơn
Các bạn giúp với :<
Bài 1:
a, CMR: A = \(\dfrac{3}{1^2.2^2}+\dfrac{5}{2^2.3^2}+\dfrac{7}{3^2.4^2}+...+\dfrac{21}{10^2.11^2}< 1\)
b, Cho B = \(\dfrac{3}{4}+\dfrac{8}{9}+\dfrac{15}{16}+\dfrac{24}{25}+...+\dfrac{2499}{2500}.\) CMR: B không phải là số nguyên.
c, So sánh: C = \(\dfrac{2}{2^1}+\dfrac{3}{2^2}+\dfrac{4}{2^3}+...+\dfrac{2021}{2^{2020}}\) với 3.
Tính nhanh :
\(C=\dfrac{1}{3}+\dfrac{-3}{4}+\dfrac{3}{5}+\dfrac{1}{57}+\dfrac{-1}{36}+\dfrac{1}{15}+\dfrac{-2}{9}\)
\(D=\dfrac{1}{2}+\dfrac{-1}{5}+\dfrac{-5}{7}+\dfrac{1}{6}+\dfrac{-3}{35}+\dfrac{1}{3}+\dfrac{1}{41}\)
\(E=\dfrac{-1}{2}+\dfrac{3}{5}+\dfrac{-1}{9}+\dfrac{1}{127}+\dfrac{-7}{18}+\dfrac{4}{35}+\dfrac{2}{7}\)
Tìm x :
\(\dfrac{1}{4}\) . \(\dfrac{2}{6}\) . \(\dfrac{3}{8}\) . \(\dfrac{4}{10}\) . .... . \(\dfrac{30}{62}\) . \(\dfrac{31}{64}\)
\(4\dfrac{2}{5}\) . 0,5 + \(1\dfrac{3}{7}\) . 14% - (0,8)
