\(\frac{-7}{12}+\frac{11}{8}-\frac{5}{9}\)
=\(\frac{19}{24}-\frac{5}{9}\)
=\(\frac{17}{72}\)
\(\frac{-7}{12}+\frac{11}{8}-\frac{5}{9}\)
=\(\frac{19}{24}-\frac{5}{9}\)
=\(\frac{17}{72}\)
2/3-6/12+1/4
4/12-18/24+5/2
-5/7*11/9+5/7*4/9
-3/8*13/11-3/8*3/11
Tính:
a) \(\dfrac{-5}{9}\)\(+\dfrac{8}{15}+\dfrac{-2}{11}+\dfrac{4}{-9}+\dfrac{7}{15}\)
b)\(\left(\dfrac{-5}{12}+\dfrac{6}{11}\right)+\left(\dfrac{7}{17}+\dfrac{5}{11}+\dfrac{5}{12}\right)\)
c) A= \(49\dfrac{8}{23}-\left(5\dfrac{7}{32}+14\dfrac{8}{23}\right)\)
d) C= \(\dfrac{-3}{7}.\dfrac{5}{9}+\dfrac{4}{9}.\dfrac{-3}{7}+2\dfrac{3}{7}\)
7 Tính nhanh tổng sau
A=(2+3+4+5+6+7+8+9+10+11+12+13)-(1+2+3+4+5+6+7+8+9+10+11+12)
a) 3/7 . 4/9 + 3/7 .−13/9
b) −5/8 . 3/11 + 5/8 .12/11
a -5/9 + 14/9
b 2/7 + 8/-3
c 9/11+ 5/7+ 20/-11+ 12/25+2/7
1/ Tính nhanh:
a. 5/7×5/11+5/11×2/9-5/7×17/11
b. 1×2+2×4+3×6+4×8+5×10/3×4+6×8+9×12+12×16+15×20
Tính nhanh
a/ (5/12 + 1/8 - 7/11) / (49/11 - 7/8 - 35/12)
b/ ( 5 - 5/3 - 5/9 - 5/27) / (-8 + 8/3 + 8/9 + 8/27) : (15 - 15/11 - 15/121) / (16 - 16/11 - 16/121)
Tính
5+(-7)+9+(-11)+13+(-15)
(-6)+8+(-10)+12+(-14)+16
1+(-3)+5+(-7)+9+(-11)
(-2)+4+(-6)+8+(-10)+12
Rút gọn : a, 3 mũ 10 . -5 mũ 21 / -5 mũ 20. 3 mũ 12
b, -11 mũ 5 . 13 mũ 7 / 11 mũ 5 . 13 mũ 8
c, 2 mũ 10 . 3 mũ 10 - 2 mũ 10 . 3 mũ 9 / 2 mũ 9 . 3 mũ 10
d, 5 mũ 11 .7 mũ 12 + 5 mũ 11 . 7 mũ 11 / 5 mũ 12 . 7 mũ 12 + 9 . 5 mũ 11 . 7 mũ 11
A=5/9+(-5/7)+(-20/48)+8/12+(-21/48)
B=(-5/9)+8/15+(-2/11)+(4/-9)+2/45
S=1/11+1/12+1/13+....+1/20
hãy so sánh S với 1/2