Thực hiện phép tính ( bằng cách hợp lí nếu có thể) :
a) 19 1/3x 3/7 - 33 1/3
b) 9x ( 1/2)^2 + 1/3
c) 15 1/4: (-5/7) - 25 1/4: (-5/7)
Giúp mk nha! Xie Xie!!
Thực hiện phép tính ( bằng cách hợp lí nếu có thể) :
a) 19 1/3x 3/7 - 33 1/3
b) 9x ( 1/2)^2 + 1/3
c) 15 1/4: (-5/7) - 25 1/4: (-5/7)
Thực hiện phép tính(tính hợp lí nếu có thể)
4/5+(-5)/4 -1/3+2/5-5/6 2/3-5/7.14/25 (2/5-5/6):8/15-(-1)^2
-3/13+(-7)/17+(-5)/19+(-10)/13+24/17+(-14)/19
\(\dfrac{4}{5}\)+\(\dfrac{-5}{4}\)=\(\dfrac{0}{4}\)
\(\dfrac{-1}{3}\)+\(\dfrac{2}{5}-\dfrac{5}{6}\)=\(\dfrac{-10}{30}+\dfrac{12}{30}-\dfrac{25}{30}\)=\(\dfrac{-23}{30}\)
\(\dfrac{2}{3}-\dfrac{5}{7}.\dfrac{14}{25}\)=\(\dfrac{2}{3}-\dfrac{2}{5}\)=\(\dfrac{10}{15}-\dfrac{6}{15}\)=\(\dfrac{4}{15}\)
a: \(=\dfrac{16-25}{20}=\dfrac{-9}{20}\)
b: \(=\dfrac{-10}{30}+\dfrac{12}{30}-\dfrac{25}{30}=-\dfrac{23}{30}\)
c: \(=\dfrac{2}{3}-\dfrac{1}{5}\cdot2=\dfrac{2}{3}-\dfrac{2}{5}=\dfrac{10-6}{15}=\dfrac{4}{15}\)
d: \(=\dfrac{12-25}{30}\cdot\dfrac{15}{8}-1=\dfrac{-13}{16}-1=\dfrac{-29}{16}\)
e: \(=\dfrac{-3}{13}-\dfrac{10}{13}-\dfrac{7}{17}+\dfrac{24}{17}-\dfrac{5}{19}-\dfrac{14}{19}=-1\)
Thực hiện phép tính (bằng cách hợp lý nếu có thể)
a) \(1\dfrac{4}{23}+\dfrac{5}{21}-\dfrac{4}{23}+0,5+\dfrac{16}{21}\)
b) \(\dfrac{3}{7}.19\dfrac{1}{3}-\dfrac{3}{7}.33\dfrac{1}{3}\)
c) \(9.\left(-\dfrac{1}{3}\right)^3+\dfrac{1}{3}\)
d) \(15\dfrac{1}{4}:\left(-\dfrac{5}{7}\right)-25\dfrac{1}{4}\left(-\dfrac{5}{7}\right)\)
Thực hiện phép tính (bằng cách hợp lí nếu có thể)
a) \(1\dfrac{4}{23}+\dfrac{5}{21}-\dfrac{4}{23}+0,5+\dfrac{16}{21}\)
b) \(\dfrac{3}{7}.19\dfrac{1}{3}-\dfrac{3}{7}.33\dfrac{1}{3}\)
c) \(9.\left(\dfrac{1}{3}\right)^3+\dfrac{1}{3}\)
d) \(15\dfrac{1}{4}:\left(-\dfrac{5}{7}\right)-25\dfrac{1}{4}:\left(-\dfrac{5}{7}\right)\)
Lời giải :
a ) \(1\dfrac{4}{23}+\dfrac{5}{21}-\dfrac{4}{23}+0,5+\dfrac{16}{21}\)
\(=\left(1\dfrac{4}{23}-\dfrac{4}{23}\right)+\left(\dfrac{5}{21}+\dfrac{16}{21}\right)+0,5\)
\(=2,5\)
b ) \(\dfrac{3}{7}.19\dfrac{1}{3}-\dfrac{3}{7}.33\dfrac{1}{3}\)
\(=\dfrac{3}{7}\left(19\dfrac{1}{3}-33\dfrac{1}{3}\right)\)
\(=\dfrac{3}{7}\left(19-33\right)\)
\(=\dfrac{3}{7}\left(-14\right)\)
\(=-6\)
c ) \(9\left(-\dfrac{1}{3}\right)^3+\dfrac{1}{3}\)
\(=9\left(-\dfrac{1}{27}\right)+\dfrac{1}{3}\)
\(=-\dfrac{1}{3}+\dfrac{1}{3}\)
\(=0\)
d ) \(15\dfrac{1}{4}\div\left(-\dfrac{5}{7}\right)-25\dfrac{1}{4}\div\left(-\dfrac{5}{7}\right)\)
\(=\left(15\dfrac{1}{4}-25\dfrac{1}{4}\right)\div\left(-\dfrac{5}{7}\right)\)
\(=-10\left(-\dfrac{7}{5}\right)\)
\(=14\)
1. Thực hiện phép tính bằng cách hợp lí nếu có thể:
a)140/27 + 7/23 + 0,5 - 5/27 + 16/23
b)3/8 * 135/5 - 256/5 * 3/8 + 19
c)25*(-1/5)3 +1/5 - 2 * (-1/2)2 -1/2
có một câu nữa : d)211/6 : (-4/5) - 271/6 : (-4/5)
a)13/2 b)9,925 c)-1 d)
tính bằng cách hợp lí {nếu có thể}
A=2/5+ -4/3 + {-1/2}
B=1/3-[{-5/4}-{1/4+3/8}]
C=15 1/4:{-5/7-25 1/4:{-5/7}
Thực hiện phép tính ( bằng cách hợp lí nếu có thể)
a) \(1\frac{4}{23}+\frac{5}{21}-\frac{4}{23}+0,5+\frac{16}{21}\)
b) \(\frac{3}{7}.19\frac{1}{3}-\frac{3}{7}.33\frac{1}{3}\)
c) \(9.\left(\frac{-1}{3}\right)^3\) + \(\frac{1}{3}\)
d) \(15\frac{1}{4};\left(\frac{-5}{7}\right)-25\frac{1}{4}:\left(\frac{-5}{7}\right)\)
a)\(1\frac{4}{23}+\frac{5}{21}-\frac{4}{23}+0,5+\frac{16}{21}\)
\(=\left(1\frac{4}{23}-\frac{4}{23}\right)+\left(\frac{5}{21}+\frac{16}{21}\right)+0,5\)
\(=1+1+0,5=2,5\)
b)\(\frac{3}{7}\cdot19\frac{1}{3}-\frac{3}{7}\cdot33\frac{1}{3}\)
\(=\frac{3}{7}\left(19\frac{1}{3}-33\frac{1}{3}\right)=\frac{3}{7}\cdot\left(-14\right)=-6\)
c) \(9\left(-\frac{1}{3}\right)^3+\frac{1}{3}=9\cdot\left(\frac{-1}{27}\right)+\frac{1}{3}=-\frac{1}{3}+\frac{1}{3}=0\)
d) \(15\frac{1}{4}:\left(-\frac{5}{7}\right)-25\frac{1}{4}:\left(-\frac{5}{7}\right)=-\frac{7}{5}:\left(15\frac{1}{4}-25\frac{1}{4}\right)=-\frac{7}{5}:\left(-10\right)=14\)
a) \(1\frac{4}{23}+\frac{5}{21}-\frac{4}{23}+0,5+\frac{16}{21}\)
\(=\frac{27}{23}+\frac{5}{21}-\frac{4}{23}+0,5+\frac{16}{21}\)
\(=\left(\frac{27}{23}-\frac{4}{23}\right)+\left(\frac{5}{21}+\frac{16}{21}\right)+0,5\)
\(=1+1+0,5\)
\(=2,5\)
b) \(\frac{3}{7}.19\frac{1}{3}-\frac{3}{7}.33\frac{1}{3}\)
\(=\frac{3}{7}.\frac{58}{3}-\frac{3}{7}.\frac{100}{3}\)
\(=\frac{3}{7}.\left(\frac{58}{3}-\frac{100}{3}\right)\)
\(=\frac{3}{7}.\left(-14\right)\)
\(=-6\)
c) \(9.\left(-\frac{1}{3}\right)^3+\frac{1}{3}\)
\(=9.\left(-\frac{1}{27}\right)+\frac{1}{3}\)
\(=-\frac{1}{3}+\frac{1}{3}\)
\(=0\)
d) \(15\frac{1}{4}:\left(-\frac{5}{7}\right)-25\frac{1}{4}:\left(-\frac{5}{7}\right)\)
\(=\frac{61}{4}:\left(-\frac{5}{7}\right)-\frac{101}{4}:\left(-\frac{5}{7}\right)\)
\(=\left(\frac{61}{4}-\frac{101}{4}\right):\left(-\frac{5}{7}\right)\)
\(=\left(-10\right):\left(-\frac{5}{7}\right)\)
\(=14\)
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Dạng 1: Thực hiện phép tính ( tính hợp lí nếu có thể ) 1)69.4258.69 2) 23.54 47.2323 3) 1500:(20.136 3 16) 4) 5.42 (517 :5 15 24)2016.100 5) 100 : 250 : 450 – 4 . 53 – 2 2 . 25 6) 2021 38 – 7 –1 2 – 20210 7) 5.( 6) 25 39 7) 5.( 6) 25 39
1 Thực hiện phép tính bằng cách hợp lí.
a)(27-514)-(486-73)
b) -23.57+23.(-43)
c) 33.(17-15)-17.(33-5)
d) 1-3+5-7+...+17-19
2: tìm số nguyên x sao cho:
a)(1-x)3 = -8
b) 3x-4 chia hết cho x+3