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24 tháng 1 2018

1.

3.10.15 - 6.5.25

= 30.15 - 30.25

= 30.(15 - 25)

= 30.(-10)

= -300

24 tháng 1 2018

    3 . 10 . 15 - 6 . 5 . 25

= 30 . 15 - 30 . 25

= 30 . (15 - 25)

= 30 . (-10)

= -300

17 tháng 4 2020

d=43/37d=43/37 × 23/15−43/3723/15−43/37 × 8/15+31/378/15+31/37

=43/37=43/37 x 23/15+43/3723/15+43/37 x (−8/15)+31/37(−8/15)+31/37

=43/37(23/15−8/15)+31/37=43/37(23/15−8/15)+31/37

=43/37.1+31/37=43/37.1+31/37

=2=2

E=−5/24E=−5/24 × 9/11−5/249/11−5/24 × 2/11+7/122/11+7/12

=−5/24(9/11+2/11)+7/12=−5/24(9/11+2/11)+7/12

=−5/24.1+7/12=−5/24.1+7/12

=3/8=3/8

a)3/7–−11/14−7/3×6/7a)3/7–−11/14−7/3×6/7

=3/7−−11/14−2=3/7−−11/14−2

=3/7+11/14−2=3/7+11/14−2

=−11/14=−11/14

b)6/5:3/2+−2/3×9/14b)6/5:3/2+−2/3×9/14

=4/5−3/7=4/5−3/7

=13/35

17 tháng 4 2020

d=43/37d=43/37 × 23/15−43/3723/15−43/37 × 8/15+31/378/15+31/37

=43/37=43/37 x 23/15+43/3723/15+43/37 x (−8/15)+31/37(−8/15)+31/37

=43/37(23/15−8/15)+31/37=43/37(23/15−8/15)+31/37

=43/37.1+31/37=43/37.1+31/37

=2=2

E=−5/24E=−5/24 × 9/11−5/249/11−5/24 × 2/11+7/122/11+7/12

=−5/24(9/11+2/11)+7/12=−5/24(9/11+2/11)+7/12

=−5/24.1+7/12=−5/24.1+7/12

=3/8=3/8

a)3/7–−11/14−7/3×6/7a)3/7–−11/14−7/3×6/7

=3/7−−11/14−2=3/7−−11/14−2

=3/7+11/14−2=3/7+11/14−2

=−11/14=−11/14

b)6/5:3/2+−2/3×9/14b)6/5:3/2+−2/3×9/14

=4/5−3/7=4/5−3/7

=13/35

a: \(=\dfrac{5}{6}\cdot\dfrac{-12}{7}=\dfrac{-10}{7}\)

b: \(=\dfrac{7}{8}\cdot\dfrac{8}{14}=\dfrac{7}{14}=\dfrac{1}{2}\)

c: \(=\dfrac{4}{5}\cdot\dfrac{-15}{8}=\dfrac{-3}{2}\)

d: \(=\dfrac{15}{16}\cdot\dfrac{8}{25}=\dfrac{15}{25}\cdot\dfrac{1}{2}=\dfrac{3}{5}\cdot\dfrac{1}{2}=\dfrac{3}{10}\)

đ: \(=\dfrac{2}{3}-\dfrac{70}{175}=\dfrac{2}{3}-\dfrac{2}{5}=\dfrac{10-6}{15}=\dfrac{4}{15}\)

a: \(=\dfrac{-5}{8}+\dfrac{7}{12}=\dfrac{-15}{24}+\dfrac{14}{24}=\dfrac{-1}{24}\)

b: \(=\dfrac{3}{4}-\dfrac{5}{6}+\dfrac{11}{12}=\dfrac{9}{12}-\dfrac{10}{12}+\dfrac{11}{12}=\dfrac{10}{12}=\dfrac{5}{6}\)

c: \(=\dfrac{6}{36}-\dfrac{1}{36}=\dfrac{5}{36}\)

d: \(=\dfrac{5}{12}+\dfrac{5}{12}=\dfrac{10}{12}=\dfrac{5}{6}\)

e: \(=\dfrac{-8}{56}-\dfrac{7}{56}=\dfrac{-15}{56}\)

f: \(=\dfrac{-5}{15}+\dfrac{3}{25}=\dfrac{-25}{75}+\dfrac{9}{75}=\dfrac{-16}{75}\)

14 tháng 2 2022

Ý A là 7/-12 nhé bạn

20 tháng 5 2022

2/3 + 3/4=17/12
9/4 + 3/5=57/20
5/24 + 1/4=11/24
3/15 - 5/35=2/35        18/27 - 2/6=1/3        37/12 - 3=1/12
11/9 x 3/22=1/6         7/13 x 13/7=1       4 x6/7=24/7
2/5 : 3/10=4/3           3/8 : 9/4=1/6            8/21 : 4/7=2/3

20 tháng 5 2022

2/3 + 3/4

= 17/12
9/4 + 3/5

= 57/20
5/24 + 1/4

=11/24
3/15 - 5/35   

=2/35   

18/27 - 2/6   

=1/3   

37/12 - 3

= 1/12
11/9 x 3/22 

=1/6       

7/13 x 13/7 

=1   

 4 x6/7

=24/7
2/5 : 3/10

=4/3         

 3/8 : 9/4   

=1/6       

8/21 : 4/7

= 2/3

19 tháng 1 2017

Bài 1:

a) \(24 - (-15) - 2\)

\(=39-2\)

\(=37\)

b) \((-85) + 10 - (-85) - 50\)

\(=[(-85)-(-85)]+10-50\)

\(=0+10-50\)

\(=10-50\)

\(=-40\)

c) \(71 - (-30) - (+18) + (-30)\)

\(=[(-30)-(-30)]+71-(+18)\)

\(=0+71-18\)

\(=71-18\)

\(=53\)

d) \(-(30) - (+37) + (+37) + (-85)\)

\(=[-(+37)+(+37)]-(30)+(-85)\)

\(=0-(30)+(-85)\)

\(=(-30)+(-85)\)

\(=-115\)

e) \((35-815) - (795-65)\)

\(=(-780)-730\)

\(=-1510\)

g) \((2002-79+15) + (-79+15)\)

\(=1938+(-64)\)

\(=1874\)

19 tháng 1 2017

Bài 2:

a) \(25 - (30+x) = x - (27-8)\)

\(25-30-x=x-27+8\)

\(x+x=25-30+27-8\)

\(2x=14\)

\(x=14\div2\)

\(x=7\)

b) \((x-12) - 15 = (20-17) - (18+x) \)

\(x-12-15=13-18-x\)

\(x-27=-5-x\)

\(x+x=-5+27\)

\(2x=22\)

\(x=22\div2\)

\(x=11\)

c) \(15 - x = 7 - (-2)\)

\(15-x=9\)

\(x=15-9\)

\(x=6\)

d) \(x - 35 = (-12) - 3\)

\(x-35=-15\)

\(x=-15+35\)

\(x=20\)

e) \(\left|5-x\right|-26=-15\)

\(\left|5-x\right|=-15+26\)

\(\left|5-x\right|=11\)

Từ đây ta có:

*Nếu \(5-x=11\)

\(x=5-11\)

\(x=-6\)

*Nếu \(5-x=-11\)

\(x=5-(-11)\)

\(x=16\)

Vậy \(x=-6;x=16\)

22 tháng 11 2018

áp dụng kiến thức tính nhanh ý

22 tháng 11 2018

1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20+21+22+23+24+25+26+27+28+29+30+31+32+33+34+35+36+37+38+39+40+41+42+43+44+45+46+47+48+49+50=1275

25 tháng 4 2018

=1275

25 tháng 4 2018

=1245