nếu 4+5=15
2+3=9
vậy 1+2=?
K
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LM
Lê Minh Vũ
CTVHS
VIP
15 tháng 6 2023
3 x 15 + 21 x 15 + 85 x 5
= 45 + 315 + 425
= 785
15 - 30 + 40
= 25
21 + 19 - 50 + 10
= 0
\(\dfrac{1}{5}-\dfrac{1}{4}+2\)
\(=-\dfrac{1}{20}+2\)
\(=\dfrac{39}{20}\)
\(\left(\dfrac{1}{4}+\dfrac{1}{6}\right)\times\left(\dfrac{1}{2}-\dfrac{1}{4}\right)\)
\(=\dfrac{5}{12}\times\dfrac{1}{4}\)
\(=\dfrac{5}{12}\times\dfrac{3}{12}\)
\(=\dfrac{5}{48}\)
\(\dfrac{1}{10}+\dfrac{1}{5}-\dfrac{3}{4}\)
\(=-\dfrac{9}{20}\)
BD
15 tháng 6 2023
\(3\times15+21\times15+85\times5\\ =15\times\left(3+21\right)+425\\ =15\times24+425\\ =360+425\\ =785\)
\(15-30+40\\ =\left(15+40\right)-30\\ =55-30\\ =25\)
\(21+19-50+10\\ =\left(21+19\right)-\left(50-10\right)\\ =40-40\\ =0\)
\(\dfrac{1}{5}-\dfrac{1}{4}+2\)
\(=\dfrac{4}{20}-\dfrac{5}{20}+\dfrac{40}{20}\)
\(=\dfrac{\left(4+40\right)}{20}-\dfrac{5}{20}\)
\(=\dfrac{44}{20}-\dfrac{5}{20}\)
\(=\dfrac{39}{20}\)
\(\left(\dfrac{1}{4}+\dfrac{1}{6}\right)\times\left(\dfrac{1}{2}-\dfrac{1}{4}\right)\)
\(=\dfrac{5}{12}\times\dfrac{1}{4}\)
\(=\dfrac{5}{48}\)
\(\dfrac{1}{10}+\dfrac{1}{5}-\dfrac{3}{4}\)
\(=\dfrac{2}{20}+\dfrac{4}{20}-\dfrac{15}{20}\)
\(=\dfrac{6}{20}-\dfrac{15}{20}\)
\(=-\dfrac{9}{20}\)
25 tháng 9 2020
a.
\(\left(1\frac{1}{4}+\frac{3}{5}\right):\left(-\frac{11}{12}\right)+\left(\frac{3}{8}-1\frac{2}{5}\right):\left(-\frac{11}{12}\right)\)
\(=\left(\frac{5}{4}+\frac{3}{5}+\frac{3}{8}-\frac{7}{5}\right):\left(-\frac{11}{12}\right)\)
\(=\left(\frac{13}{8}-\frac{4}{5}\right):\left(-\frac{11}{12}\right)\)
\(=\frac{33}{40}:\left(-\frac{11}{12}\right)\)
\(=\frac{33}{40}\cdot\left(-\frac{12}{11}\right)\)
\(=\frac{-9}{10}\)
b.
\(\left(\frac{3}{8}-1\frac{2}{5}\right):\left(-\frac{11}{15}\right)+\left(1\frac{1}{4}+\frac{3}{5}\right):\left(-\frac{11}{15}\right)\)
\(=\left(\frac{3}{8}-\frac{7}{5}+\frac{5}{4}+\frac{3}{5}\right):\left(-\frac{11}{15}\right)\)
\(=\left(\frac{13}{8}-\frac{4}{5}\right):\left(-\frac{11}{15}\right)\)
\(=\frac{33}{40}:\left(-\frac{11}{15}\right)\)
\(=\frac{33}{40}\cdot\left(-\frac{15}{11}\right)\)
\(=\frac{-9}{8}\)
2 tháng 5 2018
Bài làm
1.
11 3/13 - ( 2 4/7 + 5 3/13 )
= 11 3/13 - 2 4/7 - 5 3/13
= ( 11 3/13 - 5 3/13 ) - 2 4/7
= { (11 - 5 ) . ( 3/13 - 3/13 ) } - 2 4/7
= ( 6 . 0 ) - 2 4/7
= 0 - 2 4/7
= 2 4/7
= 18/7
2 .
19 5/8 : 7/12 + ( -15 1/4) : 7/12
= { 19 5/8 + ( -15 1/4 ) } : 7/12
= [ { 19 + ( - 15) } . ( 5/8 + 1/4 ) ] : 7/12
= { 4 . ( 5/8 + 2/8 ) } : 7/12
= ( 4 . 7/8 ) : 7/12
= 1.7/2 : 7/12
= 7/2 : 7/12
= 7/2 . 12/7
= 1.1/6.1
= 1/6
3 .
2/5 . 1/3 - 2 2/15 : 1/5 + 3/5 . 1/3
= 1/3 . ( 2/5 + 3/5 ) - 2 2/15 : 1/5
= 1/3 . 5/5 - 32/15 . 5/1
= 1/3 . 1 - 32.1/3.1
= 1/3 - 32/3
= -31/3
4 .
( 3 1/3 + 2,5 ) : ( 3 1/6 - 4 1/5 ) - 11/31
= ( 10/3 + 25/10 ) : { ( 3 - 4 ) . ( 1/6 - 1/5 ) - 11/31
= ( 10/3 + 5/2 ) : { (-1) . ( 5/30 - 6/30 ) } - 11/31
= ( 20/6 + 15/6 ) : { (-1) . (-1)/30 } - 11/31
= 35/6 : 1/30 - 11/31
= 35/6 . 30/1 - 11/31
= 35.5/1.1 - 11/31
= 175 - 11/31
= 5425/31 - 11/31
= 5414/31
5.
75% - 1 1/5 + 0,5 : 5/12 - (-1/2)2
= 75/100 - 6/5 + 5/12 - 1/4
= 3/4 - 6/5 + 5/12 - 1/4
= ( 3/4 - 1/4 ) + ( 5/12 - 6/5 )
= 2/4 + ( 25/60 - 30/60 )
= 1/2 + (-5)/60
= 1/2 + (-1)/12
= 6/12 + (-1)/12
= 5/12
Đúng thì k cho mình nha !
2 tháng 5 2018
1)
11 3/13 - ( 2 4/7 + 5 3/13 )
= 11 3/13 - 2 4/7 - 5 3/13
= ( 11 3/13 - 5 3/13 ) - 2 4/7
= { (11 - 5 ) . ( 3/13 - 3/13 ) } - 2 4/7
= ( 6 . 0 ) - 2 4/7
= 0 - 2 4/7
= 2 4/7
= 18/7
2 )
19 5/8 : 7/12 + ( -15 1/4) : 7/12
= { 19 5/8 + ( -15 1/4 ) } : 7/12
= [ { 19 + ( - 15) } . ( 5/8 + 1/4 ) ] : 7/12
= { 4 . ( 5/8 + 2/8 ) } : 7/12
= ( 4 . 7/8 ) : 7/12
= 1.7/2 : 7/12
= 7/2 : 7/12
= 7/2 . 12/7
= 1.1/6.1
= 1/6
3 )
2/5 . 1/3 - 2 2/15 : 1/5 + 3/5 . 1/3
= 1/3 . ( 2/5 + 3/5 ) - 2 2/15 : 1/5
= 1/3 . 5/5 - 32/15 . 5/1
= 1/3 . 1 - 32.1/3.1
= 1/3 - 32/3
= -31/3
4 )
( 3 1/3 + 2,5 ) : ( 3 1/6 - 4 1/5 ) - 11/31
= ( 10/3 + 25/10 ) : { ( 3 - 4 ) . ( 1/6 - 1/5 ) - 11/31
= ( 10/3 + 5/2 ) : { (-1) . ( 5/30 - 6/30 ) } - 11/31
= ( 20/6 + 15/6 ) : { (-1) . (-1)/30 } - 11/31
= 35/6 : 1/30 - 11/31
= 35/6 . 30/1 - 11/31
= 35.5/1.1 - 11/31
= 175 - 11/31
= 5425/31 - 11/31
= 5414/31
5)
75% - 1 1/5 + 0,5 : 5/12 - (-1/2)2
= 75/100 - 6/5 + 5/12 - 1/4
= 3/4 - 6/5 + 5/12 - 1/4
= ( 3/4 - 1/4 ) + ( 5/12 - 6/5 )
= 2/4 + ( 25/60 - 30/60 )
= 1/2 + (-5)/60
= 1/2 + (-1)/12
= 6/12 + (-1)/12
= 5/12
9 tháng 1 2018
vì 1 x 5 =5
2 x 5 =10
3 x 5 =15
4 x 5 =20
vaayj5 x 5 =25
T
25 tháng 11 2023
1) \(\left(+15\right)+\left(+17\right)=15+17=32\)
2) \(\left(-3\right)+\left(-7\right)=-3-7=-\left(3+7\right)=-10\)
3) \(\left(-25\right)+\left(+4\right)=-25+4=-\left(25-4\right)=-21\)
4) \(\left(-6\right)+\left(-54\right)=-6-54=-\left(6+54\right)=-60\)
5) \(\left(-15\right)+20=20-15=5\)
6) \(\left(-5\right)+8+7+5\)
\(=\left(-5+5\right)+\left(8+7\right)\)
\(=15\)
7) \(\left(-8\right)+\left(-11\right)+\left(-2\right)\)
\(=\left[\left(-8\right)+\left(-2\right)\right]+\left(-11\right)\)
\(=\left(-10\right)+\left(-11\right)\)
\(=-21\)
8) \(15+\left(-5\right)+\left(-14\right)+\left(-16\right)\)
\(=\left[15+\left(-5\right)\right]+\left[\left(-14\right)+\left(-16\right)\right]\)
\(=10+\left(-30\right)\)
\(=-20\)
9) \(\left(-20\right)+\left(-14\right)+3+\left(-86\right)\)
\(=\left[\left(-20\right)+3\right]+\left[\left(-14\right)+\left(-86\right)\right]\)
\(=\left(-17\right)+\left(-100\right)\)
\(=-117\)
10) \(\left(-136\right)+123+\left(-264\right)+\left(-83\right)+240\)
\(=\left[\left(-136\right)+\left(-264\right)\right]+\left[123+\left(-83\right)\right]+240\)
\(=\left(-400\right)+40+240\)
\(=\left(-360\right)+240\)
\(=-120\)
11) \(\left(-596\right)+2001+1999+\left(-404+189\right)\)
\(=\left(-596\right)+2001+1999-404+189\)
\(=\left[\left(-596\right)-404\right]+\left(2001+189\right)+1999\)
\(=\left(-1000\right)+2190+1999\)
\(=1190+1999\)
\(=3189\)
12) \(314+\left(-153\right)+64+121+\left(-247\right)+218\)
\(=\left(314+64+121\right)+\left[\left(-153\right)+\left(-247\right)\right]+218\)
\(=\left(378+121\right)+\left(-400\right)+218\)
\(=499-400+218\)
\(=99+218\)
\(=317\)
\(\text{#}Toru\)
CW
25 tháng 6 2016
a) \(\frac{3}{5}:\left(-\frac{1}{15}-\frac{1}{6}\right)+\frac{3}{5}:\left(-\frac{1}{3}-1\frac{1}{15}\right)\)
\(=\frac{3}{5}:\left(-\frac{1}{15}-\frac{1}{6}-\frac{2}{6}-1+\frac{1}{15}\right)\)
\(=\frac{3}{5}:\left(-\frac{1}{2}-1\right)\)
\(=\frac{3}{5}:\left(-\frac{3}{2}\right)\)
\(=-\frac{2}{5}\)
CW
25 tháng 6 2016
b) \(\left(-\frac{3}{4}+\frac{5}{13}\right):\frac{2}{7}-\left(2\frac{1}{4}+\frac{8}{13}\right):\frac{2}{7}\)
\(=\left(-\frac{3}{4}+\frac{5}{13}-2+\frac{1}{4}+\frac{8}{13}\right):\frac{2}{7}\)
\(=\left(-\frac{1}{2}+1-2\right):\frac{2}{7}\)
\(=\left(-\frac{1}{2}-1\right):\frac{2}{7}\)
\(=-\frac{3}{2}:\frac{2}{7}\)
\(=-\frac{21}{4}\)
15 tháng 9 2021
1=5,2=10,3=15,4=20 thì 5=25 vì ở đó có tất cả các số nhân cho năm là ra kết quả
S
10 tháng 3 2023
\(\dfrac{4}{5}\)+\(\dfrac{-5}{4}\)=\(\dfrac{0}{4}\)
\(\dfrac{-1}{3}\)+\(\dfrac{2}{5}-\dfrac{5}{6}\)=\(\dfrac{-10}{30}+\dfrac{12}{30}-\dfrac{25}{30}\)=\(\dfrac{-23}{30}\)
\(\dfrac{2}{3}-\dfrac{5}{7}.\dfrac{14}{25}\)=\(\dfrac{2}{3}-\dfrac{2}{5}\)=\(\dfrac{10}{15}-\dfrac{6}{15}\)=\(\dfrac{4}{15}\)
7
chắc vậy
số đó là 5