-3/5--19/24+-7/24
Cho A =19/24 - 1/2 -1/3 - 7/24
B= 7/12 + 5/6 + 1/4 - 3/7 - 5/12
So sánh:A=19/24-1/2-1/3-7/24 và B=7/12+5/6+1/4-3/7-5/12-3
A= -3/3 - 7/17 + -5/19 + 10/13 + 24/27 - 14/19
B= 1,25 * 7/19 + 5/4 * 15/19 - 1* 1/4 / 19/3
- 3/13 - 7/17 + (-5/19) + (- 10/13) + 24/17 - 4/19
\(-\dfrac{3}{13}-\dfrac{7}{17}+\left(-\dfrac{5}{19}\right)+\left(-\dfrac{10}{13}\right)+\dfrac{24}{17}-\dfrac{4}{19}\)
\(=\left(-\dfrac{3}{13}-\dfrac{10}{13}\right)-\left(\dfrac{7}{17}-\dfrac{24}{17}\right)+\left(-\dfrac{5}{19}-\dfrac{4}{19}\right)\)
\(=-\dfrac{13}{13}-\left(-\dfrac{17}{17}\right)+-\dfrac{9}{19}\)
\(=-1+1+-\dfrac{9}{19}=-\dfrac{9}{19}\)
\(\dfrac{-3}{13}-\dfrac{7}{17}+\left(\dfrac{-5}{19}\right)+\left(\dfrac{-10}{13}\right)+\dfrac{24}{17}-\dfrac{4}{19}\)
=\(\left(\dfrac{-3}{13}+\dfrac{-10}{13}\right)+\left(\dfrac{-7}{17}+\dfrac{24}{17}\right)+\left(\dfrac{-5}{19}-\dfrac{4}{19}\right)\)
=-1+1+\(\dfrac{-9}{19}\)
=0+\(\dfrac{-9}{19}\) =\(\dfrac{-9}{19}\)
SS A và B
A=\(\dfrac{19}{24}-\dfrac{1}{2}-\dfrac{1}{3}-\dfrac{7}{24}\)
B=\(\dfrac{7}{24}+\dfrac{5}{6}+\dfrac{1}{4}-\dfrac{3}{7}-\dfrac{5}{15}\)
\(A=\frac{19}{24}-\frac{1}{2}-\frac{1}{3}-\frac{7}{24}\)
\(A=\frac{19}{24}+\frac{-1}{2}+\frac{-1}{3}+\frac{-7}{24}\)
\(A=\left(\frac{19}{24}+\frac{-7}{24}\right)+\frac{-1}{2}+\frac{-1}{3}\)
\(A=\frac{1}{2}+\frac{-1}{2}+\frac{-1}{3}\)
\(A=0+\frac{-1}{3}=\frac{-1}{3}\)
\(B=\frac{7}{24}+\frac{5}{6}+\frac{1}{4}-\frac{3}{7}-\frac{5}{15}\)
\(B=\frac{7}{24}+\frac{5}{6}+\frac{1}{4}+\frac{-3}{7}+\frac{-1}{3}\)
\(B=\left(\frac{49}{168}+\frac{140}{168}+\frac{42}{168}\right)+\left(\frac{-72}{168}+\frac{-56}{168}\right)\)
\(B=\frac{231}{168}+\frac{-128}{168}=\frac{103}{168}\)
Có: \(A=\frac{-1}{3}=\frac{\left(-1\right)\cdot56}{3\cdot56}=\frac{-56}{168}\)
Mặt khác: \(-56< 103\)
\(\Rightarrow\)\(\frac{-56}{168}< \frac{103}{168}\)
\(hay\) \(A< B\)
SS A và B
A=\(\frac{19}{24}-\frac{1}{2}-\frac{1}{3}-\frac{7}{24}\)
B=\(\frac{7}{24}+\frac{5}{6}+\frac{1}{4}-\frac{3}{7}-\frac{5}{15}\)
\(A=\frac{19}{24}-\frac{1}{2}-\frac{1}{3}-\frac{7}{24}\)
\(A=\frac{19}{24}-\frac{12}{24}-\frac{8}{24}-\frac{7}{24}\)
\(A=\frac{19-12-8-7}{24}\)
\(A=\frac{-8}{24}\)\(=\frac{-1}{3}\)
\(B=\frac{7}{24}+\frac{5}{6}+\frac{1}{4}-\frac{3}{7}-\frac{5}{15}\)
\(B=\frac{7}{24}+\frac{30}{24}+\frac{6}{24}-\frac{3}{7}-\frac{1}{3}\)
\(B=\frac{7}{24}+\frac{30}{24}+\frac{6}{24}-\frac{3}{7}-\frac{8}{24}\)
\(B=\frac{7+30+6-8}{24}-\frac{3}{7}\)
\(B=\frac{21}{24}-\frac{3}{7}\)
\(B=\frac{7}{8}-\frac{3}{7}\)
\(\Rightarrow B=\frac{25}{56}\)
A = -3/13 – 7/17 + -5/19 + 10/13 + 24/17 – 14/19
b) B = 1,25 . 7/19 + 5/4 . 15/19 – 1.1/4 : 19/3
hợp lý nha , dễ mà .......................
B1: Bỏ ngoặc rồi thực hiện phép tính (phân số)
a) (-5/11) - (7/19 - 5/31)
b) - ( 11/14 - 8/19) + (3/14 - 8/19)
B2: Tím số nguyên x, biết
-5/24 - 1/3 < x/24 < -1/8 + 1/3
1. tính nhanh giá trị của mỗi buổi thức sau:
a) -3/-7+5/19+-4/7
b)-13/24+-5/24+7/21
c)-5/13+(-8/13+1)
d)2/3+(3/8+-2/3)
e)(-3/4+5/8)+-1/8