Thực hiện phép tính:
A =\(\frac{5.\left(2^2.3^2\right)^9.\left(2^2\right)^6-2.\left(2^2.3\right)^{14}.3^4}{5.2^{28}.3^{18}-7.2^{29}.3^{18}}\)
B= \(81.\frac{12-\frac{12}{7}-\frac{12}{289}-\frac{12}{85}5+\frac{5}{13}+\frac{5}{169}+\frac{5}{91}}{4-\frac{4}{7}-\frac{4}{289}-\frac{4}{85}6+\frac{6}{13}+\frac{6}{169}+\frac{6}{91}}.\frac{158158158}{711711711}\)
Thực hiện phép tính:A=81.[12-12/7-12-298-12/85/4-4/7-4/289-4/85:4+5/13+5/169+5/91/6+6/13+6/169+6/91].158158158/711711711
Tính N = \(\frac{5.\left(2^2.3^2\right)^9.\left(2^2\right)^6-2.\left(2^2.3\right)^{14}.3^6}{5.2^{28}.3^{19}-7.2^{29}.3^{18}}\)
tính hợp lí ( nếu có thể )
\(B=\left(\frac{2}{3}-\frac{1}{4}+\frac{5}{11}\right):\left(\frac{5}{12}+1-\frac{7}{11}\right)\)
\(C=\left(-\frac{14}{33}\right).2\frac{4}{9}+\frac{48}{25}:\frac{27}{25}\)
\(D=\left(3-2\frac{1}{3}+\frac{1}{4}\right):\left(4-5\frac{1}{6}+2\frac{1}{4}\right)\)
\(G=\left(7\frac{1}{9}-2\frac{14}{15}\right):\left(2\frac{2}{3}-6\frac{2}{3}\right)-\frac{32}{45}\)
\(H=-\frac{1}{7}.\left(9\frac{1}{2}-8,75\right):\frac{2}{7}+0,625:1\frac{2}{3}\)
Bài 1: a) \(A=\frac{5}{11.16}+\frac{5}{16.21}+\frac{5}{21.26}+...+\frac{5}{61.66}\)
b) \(B=\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+\frac{1}{30}+\frac{1}{42}\)
c) \(C=\frac{1}{1.2}+\frac{1}{2.3}+...+\frac{1}{1989.1990}\)
Bài 2: a. Tính tổng: \(M=\frac{10}{56}+\frac{10}{140}+\frac{10}{260}+...+\frac{10}{1400}\)
b. Cho: \(S=\frac{3}{10}+\frac{3}{11}+\frac{3}{12}+\frac{3}{13}+\frac{3}{14}\) chứng minh rằng 1 < S < 2
Bài 3: Tính giá trị của biểu thức sau:
\(A=\left(\frac{1}{7}+\frac{1}{23}-\frac{1}{1009}\right):\left(\frac{1}{23}+\frac{1}{7}-\frac{2}{2009}+\frac{1}{7}.\frac{1}{23}.\frac{1}{2009}\right)+1:\left(30.1009-160\right)\)
Bài 4: Tính nhanh:
\(\text{a) 35 . 34 + 35 . 86 + 67 . 75 + 65 . 45}\)
\(\text{b) 21 . }7^2-11.7^2+90.7^2+49.125.16\)
Bài 5: Thực hiện phép tinh sau:
a. \(\frac{2181.729+243.81.27}{3^2.9^2.234+18.54+162.9+723.729}\)
b. \(\frac{1}{1.2+}+\frac{1}{2.3}+\frac{1}{3.4}+...+\frac{1}{98.99}+\frac{1}{99.100}\)
c. \(\frac{1}{2^2}+\frac{1}{3^2}+\frac{1}{4^2}+...+\frac{1}{100^2}< 1\)
d. \(\frac{5.4^{15}-9^9-4.3^{20}}{5.2^{19}.6^{19}-7.2^{29}.27^6}\)
giúp mk nha! nhớ viết cách làm nha!
Rút gọn
1.\(\left(\frac{2}{45}-\frac{4}{13}-\frac{1}{3}\right):\left(\frac{3}{13}-\frac{4}{15}+\frac{2}{13}\right)\)
2.\(\frac{0,8:\left(\frac{4}{5}.1,25\right)}{0,64-\frac{1}{25}}+\frac{\left(1,08-\frac{2}{15}\right):\frac{4}{7}}{\left(6\frac{5}{9}-3\frac{1}{4}\right)2\frac{2}{17}}\)
3.\(\frac{0,4-\frac{2}{9}+\frac{2}{11}}{1,4-\frac{7}{9}+\frac{7}{11}}-\frac{\frac{1}{3}-0,25+\frac{1}{5}}{1\frac{1}{6}-0,875+0,7}\)
Bài 3: Thực hiện phép tính một cách hợp lý:
m) \(\left(\frac{-5}{12}+\frac{6}{11}\right)+\left(\frac{7}{17}+\frac{5}{11}+\frac{5}{12}\right)\) n) \(\left(\frac{9}{16}+\frac{8}{-27}\right)+\left(1+\frac{7}{16}+\frac{-19}{27}\right)\) o) \(\left(6-2\frac{4}{5}\right).3\frac{1}{8}-1\frac{3}{5}:\frac{1}{4}\)
tính hợp lý giá trị các biểu thức sau :
A= \(49\frac{8}{23}-\left(5\frac{7}{32}+14\frac{8}{23}\right)\)
B= \(71\frac{38}{45}-\left(43\frac{8}{45}-1\frac{17}{57}\right)\)
C= \(\frac{-3}{7}.\frac{5}{9}+\frac{4}{9}.\frac{-3}{7}+2\frac{3}{7}\)
D = \(\left(19\frac{5}{8}:\frac{7}{12}-13\frac{1}{4}:\frac{7}{12}\right).\frac{4}{5}\)
E= \(0,7.2\frac{2}{3}.20.0,375.\frac{5}{28}\)
F= \(\left(9,75.21\frac{3}{7}+\frac{39}{4}.18\frac{4}{7}\right).\frac{15}{78}\)
tính hợp lí nếu có thể
\(-\frac{1}{4}\times13\frac{9}{11}-0,25\times6\frac{2}{11}\)
\(B=\frac{-5}{6}\times\frac{4}{19}+\frac{-7}{12}\times\frac{4}{19}-\frac{40}{57}\)
\(\frac{3}{7}\times\frac{9}{26}-\frac{1}{14}\times\frac{1}{13}-\frac{1}{7}\)
\(\frac{4}{9}:\left(-\frac{1}{7}\right)+6\frac{5}{9}:\left(-\frac{1}{7}\right)\)
