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A =\(\frac{2}{5}\times\frac{4}{7}+\frac{3}{5}\times\frac{4}{7}\) B = \(\frac{17}{13}\times\frac{12}{17}-\frac{4}{13}\times\frac{12}{17}\) C = \(\frac{9}{14}:\frac{6}{7}+\frac{5}{14}:\frac{6}{7}\) D =\(\frac{9}{12}:\frac{7}{9}\times\frac{12}{19}\)
= \(\frac{4}{7}\times\left(\frac{2}{5}+\frac{3}{5}\right)\) =\(\left(\frac{17}{13}-\frac{4}{13}\right)\times\frac{12}{17}\) = \((\frac{9}{14}+\frac{5}{14}):\frac{6}{7}\) = \(\frac{9}{12}\times\frac{9}{7}\times\frac{12}{19}\)
=\(\frac{4}{7}\times1\) = \(1\times\frac{12}{17}\) = \(1:\frac{6}{7}\) = \(\frac{9\times9\times12}{12\times7\times19}\)
=\(\frac{4}{7}\) = \(\frac{12}{17}\) =\(\frac{7}{6}\) = \(\frac{9\times9}{7\times19}=\frac{81}{133}\)
\(1,\\ c,\dfrac{17}{6}-\dfrac{3}{7}-\dfrac{5}{6}=\dfrac{17\times7-3\times6-5\times7}{6\times7}=\dfrac{119-18-35}{42}=\dfrac{66}{42}=\dfrac{11}{7}\\ 2,\\ a,\dfrac{6}{9}+\dfrac{3}{15}+\dfrac{7}{15}\\ =\dfrac{6:3}{9:3}+\dfrac{7+3}{15}\\ =\dfrac{2}{3}+\dfrac{10}{15}\\ =\dfrac{2}{3}+\dfrac{2}{3}\\ =\dfrac{2+2}{3}=\dfrac{4}{3}\)
\(b,\dfrac{7}{2}+\dfrac{29}{12}-\dfrac{11}{12}\\ =\dfrac{7}{2}+\left(\dfrac{29}{12}-\dfrac{11}{12}\right)\\ =\dfrac{7}{2}+\dfrac{29-11}{12}\\ =\dfrac{7}{2}+\dfrac{18}{12}\\ =\dfrac{7}{2}+\dfrac{18:6}{12:6}\\ =\dfrac{7}{2}+\dfrac{3}{2}\\ =\dfrac{7+3}{2}=\dfrac{10}{2}=5\)
\(c,\dfrac{26}{25}-\dfrac{3}{5}-\dfrac{2}{5}\\ =\dfrac{26}{25}-\dfrac{3\times5}{5\times5}-\dfrac{2\times5}{5\times5}\\ =\dfrac{26-15-10}{25}\\ =\dfrac{1}{25}\)
Bài 1:
\(\dfrac{17}{6}-\dfrac{3}{7}-\dfrac{5}{6}=\left(\dfrac{17}{6}-\dfrac{5}{6}\right)-\dfrac{3}{7}=2-\dfrac{3}{7}=\dfrac{14}{7}-\dfrac{3}{7}=\dfrac{11}{7}\)
Bài 2:
a/\(\dfrac{6}{9}+\dfrac{3}{15}+\dfrac{7}{15}\)
\(=\dfrac{2}{3}+\left(\dfrac{3}{15}+\dfrac{7}{15}\right)\)
\(=\dfrac{2}{3}+\dfrac{2}{3}\)
\(=\dfrac{4}{3}\)
b/\(\dfrac{7}{2}+\dfrac{29}{12}-\dfrac{11}{12}\)
\(=\dfrac{7}{2}+\left(\dfrac{29}{12}-\dfrac{11}{12}\right)\)
\(=\dfrac{7}{2}+\dfrac{3}{2}\)
\(=5\)
c/\(\dfrac{26}{25}-\dfrac{3}{5}-\dfrac{2}{5}\)
\(=\dfrac{26}{25}-\left(\dfrac{3}{5}+\dfrac{2}{5}\right)\)
\(=\dfrac{26}{25}-1\)
\(=\dfrac{26}{25}-\dfrac{25}{25}\)
\(=\dfrac{1}{25}\)
#Đang Bận Thở
a,17/23 + (1 - 17/23)
= 17/23 + 6/23
= 23/23 = 1
b,17/12 + 9/7 - (2/7 + 5 /12)
= (17/12 - 5/12) + (9/7 + 2/7)
= 1+1 = 2
c, 7/13 - ( 4/7 -6/13 )
= 7/13 - 4/7+ 6/13
= (7/13 + 6/13) -4/7
= 13/13 -4/7
= 1 -4/7 = 3/7
hok tốt✍️ ✍️
a) 17/23+(1-17/23)
=17/23+1-17/23
=1
b)17/12+9/7-(2/7+5/12)
=17/12+9/7-2/7-5/12
=1+1
=2
c)
7/13-(4/7-6/13)
=7/13-4/7+6/13
=1-4/7
=3/7
a) 17/23 + (1 - 17/23)
= 17/23 + 1 - 17/23
= (17/23 - 17/23) + 1
= 0 + 1 = 1
b) 17/12 + 9/7 - (2/7 + 5/12)
= 17/12 + 9/7 - 2/7 - 5/12
= (17/12 - 5/12) + (9/7 - 2/7)
= 1 + 1 = 2
c) 7/13 - (4/7 - 6/13)
= 7/13 - 4/7 + 6/13
= (6/13 + 6/12) - 4/7
= 1 - 4/7 = 3/7
d) 7/18 + 3/16 + 11/18 + 13/16
= (7/18 + 11/18) + (3/16 + 13/16)
= 1 + 1 = 1
d) sửa 7/18 + 3/16 + 11/18 + 13/16
= (7/18 + 11/18) + (3/16 + 13/16)
= 1 + 1
= 2
( 1/10 + 2/9 + 3/8 + 4/7 + 5/6 + 1/6 + 3/7 + 5/8 + 7/9 + 9/10 ) * 48
= [ ( 1/10 + 9/10 ) + ( 2/9 + 7/9 ) + ( 3/8 + 5/8 ) + ( 4/7 + 3/7 ) + ( 5/6 + 1/6 ) ] * 48
=( 1 + 1 + 1 + 1 + ) *48
=5 * 48
= 240
21+22+23+24+25+26+9+8+7+6+5+4 =180
mình thấy rồng con lon ton làm đúng đấy
a) 8 × 5 × 9 = (8 × 5) × 9 = 40 × 9 = 360
b) 6 × 7 × 5 = (6 × 5) × 7= 30 × 7= 210
c) 6 × 4 × 25 = 6 × (4 × 25) = 6 × 100= 600
a) 5/11 + 4/7 + 6/11 + 10/7 = (5/11 + 6/11) + (4/7 + 10/7)
= 1 + 2 = 3
b) 15/9 + 5/8 - 5/9 + 11/8 = (15/9 - 5/9) + (5/8 + 11/8)
= 10/9 + 2 = 28/9
c) 21/12 + 4/11 + 7/11 - 11/12 = (21/12 - 11/12) + (4/11 + 7/11)
= 10/12 + 1 = 11/6
(4/7+10/7)+(11/9+7/9)
=14/7+18/9=2+2
=4
(1/6+5/6)+7/12+5/12)
=1+1
=2
(1/26+12/26)+(7/30+8/30)
=13/26+15/30=1/2+1/2
=2/4=1/2
(6/25+9/25)+(17/48+7/48)
=15/25+24/48=3/5+4/8
=24/40+20/40=12/20+10/20
22/20=11/10