Ta có:\(\dfrac{11}{24}-\dfrac{5}{41}+\dfrac{13}{24}+0,5-\dfrac{36}{41}\)
\(=\left(\dfrac{11}{24}+\dfrac{13}{24}\right)-\left(\dfrac{5}{41}+\dfrac{36}{41}\right)+0,5\)
\(=1-1+0,5\)
\(=0,5\)
Tính bằng cách hợp lý nhất : a) -2/3+(-1)/5+3/4-5/6-7/10 b) 0,5+1/3+0,4+5/7+1/6-4/35 c) 1/3+(-1)/5-(-1)/4-7/9-(-5)/12+(-1)/45+1/41
(409/13 + 214/41 ) - 470/13 = ?
Tính nhanh :
\(B=\dfrac{1}{5}-\dfrac{3}{7}+\dfrac{5}{9}-\dfrac{2}{11}+\dfrac{7}{13}-\dfrac{9}{16}-\dfrac{7}{13}+\dfrac{2}{11}-\dfrac{5}{9}+\dfrac{3}{7}-\dfrac{1}{5}\)
tinh nhanh
A=\(\dfrac{1}{3}-\dfrac{3}{4}-\left(\dfrac{-3}{5}\right)+\dfrac{1}{64}-\dfrac{2}{9}-\dfrac{1}{36}+\dfrac{1}{15}\)
B=\(\dfrac{1}{3}-\dfrac{3}{5}+\dfrac{5}{7}-\dfrac{7}{9}+\dfrac{9}{11}-\dfrac{11}{3}+\dfrac{13}{15}+\dfrac{11}{15}-\dfrac{9}{11}+\dfrac{7}{9}+\dfrac{7}{9}-\dfrac{5}{7}+\dfrac{3}{3}-\dfrac{1}{3}\)
giup minh nhe minh dang can gap
Tính nhanh
1/5-3/7+5/9-2/11+7/13-9/16-7/13+2/11-5/9+3/7-1/5
B=\(\frac{1}{3}-\frac{3}{4}-\left(-0,6\right)+\frac{1}{64}-\frac{2}{9}-\frac{1}{36}+\frac{1}{15}\)
C=\(\frac{1}{3}-\frac{3}{5}+\frac{5}{7}-\frac{7}{9}+\frac{9}{11}-\frac{11}{13}+\frac{13}{15}+\frac{11}{15}+\frac{11}{13}-\frac{9}{11}+\frac{7}{9}-\frac{5}{7}+0,6-\frac{1}{3}\)
D=\(\frac{1}{99}-\frac{1}{99.98}-\frac{1}{98.97}.....-\frac{1}{3.2}-\frac{1}{2.1}\)
a) 1/2 - (- 2/5) + 1/3 + 5/7 - (- 1/6) + (- 4/35) + 1/41
b) 1/ 100.99 - 1/ 99.98 - 1/ 98.97 - ..... - 1/ 3.2 - 1/ 2.1
Tính hợp lý:
a, \(\dfrac{-3}{4}.5\dfrac{3}{13}-0,75.\dfrac{36}{13}\)
b, \(4\dfrac{5}{9}:\left(\dfrac{-5}{7}\right)+\dfrac{49}{9}:\left(\dfrac{-5}{7}\right)\)
c, \(\left(\dfrac{-3}{5}+\dfrac{4}{9}\right):\dfrac{7}{11}+\left(\dfrac{-2}{5}+\dfrac{5}{9}\right):\dfrac{7}{11}\)
d, \(\dfrac{6}{7}:\left(\dfrac{3}{26}-\dfrac{3}{13}\right)+\dfrac{6}{7}:\left(\dfrac{1}{10}-\dfrac{8}{5}\right)\)
\(\dfrac{0,75-0,6+\dfrac{3}{7}+\dfrac{3}{13}}{2,75-2,2+\dfrac{11}{7}+\dfrac{11}{3}}=\dfrac{\dfrac{3}{4}-\dfrac{3}{5}+\dfrac{3}{7}+\dfrac{3}{13}}{\dfrac{11}{4}-\dfrac{11}{5}+\dfrac{11}{7}+\dfrac{11}{13}}\)
