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\(a,\dfrac{7}{9}-\dfrac{2}{7}+\dfrac{2}{3}+\dfrac{4}{7}\\ =\left(\dfrac{7}{9}+\dfrac{6}{9}\right)+\left(\dfrac{4}{7}-\dfrac{2}{7}\right)\\ =\dfrac{13}{9}+\dfrac{2}{7}\\ =\dfrac{109}{63}\\ b,13,8+7-5,25+4,25\\ =\left(13,8+7\right)-\left(5,25-4,25\right)\\ =20,8-1\\ =19,8\)
a)\(\frac{7}{9}-\frac{3}{7}+\frac{2}{3}-\frac{4}{7}\)
\(=\frac{7}{9}+\frac{-3}{7}+\frac{2}{3}+\frac{-4}{7}\)
\(=\left(\frac{7}{9}+\frac{2}{3}\right)+\left(\frac{-3}{7}+\frac{-4}{7}\right)\)
\(=\frac{13}{9}-1\)
\(=\frac{4}{9}\)
b)13,8 + 7 - 5,25 + 4,25
=(13,8 + 7 + 4,25 ) - 5,25
=25,05 - 5,25
=19,8
a) 7/9 - 3/7 + 2/3 - 4/7
= 7/9 - 3/7 + 6/9 - 4/7
=( 7/9 - 6/9 ) + ( 3/7 + 4/7 )
= 1/9 + 1
=10/9
b) 13,8 + 7 - 5,25 + 4,25
=(13,8 + 7 ) - (5,25 + 4,25 )
=20,8 - 9,5
= 11,3
\(\dfrac{8}{13}+\dfrac{4}{9}+\dfrac{1}{3}+\dfrac{5}{13}+3\)
\(=1+\dfrac{7}{9}+3\)
\(=4+\dfrac{7}{9}=\dfrac{43}{9}\)
Câu 1:
Câu 2:
b) 1/12 + 3/16 + 5/12 + 5/16
=(1/12 + 5/12) + (3/16 + 5/16)
=1/2 + 1/2
=2/2
=1
a) 1/2 + 3/16 + 5/12 + 5/16
=5/12 + (1/2 + 3/16 + 5/16)
= 5/12 + 1
= 15/12
(Đúng tick, sai bảo)
= 5,25 x (18 - 7 - 1)
= 5,25 x 10
= 52,5
9,67 x 80 x 1,25
= 9,67 x 100
= 967
c)=13,8+(7+4,25)-5,25
=13,8+(11.25-5.25)
=13,8+6=19,8
b, = 7/9 - 2/3 - < 4/7 =3/7 >
= 13/9 - 1
= 4/9