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\(\frac{1}{5}+\frac{5}{7}+\frac{1}{8}+\frac{13}{8}+\frac{4}{5}+\frac{4}{7}\)
\(=\left(\frac{1}{5}+\frac{4}{5}\right)+\left(\frac{5}{7}+\frac{4}{7}\right)+\left(\frac{1}{8}+\frac{13}{8}\right)\)
\(=1+\frac{9}{7}+\frac{7}{4}\)
\(=\frac{28}{28}+\frac{36}{28}+\frac{49}{28}\)
\(=\frac{113}{28}\)
Ai k mik mik k lại
Bài 4:
a: =11/21(7/4+5/4)=11/21x3=11/7
b: =6/13(23/14-9/14)=6/13
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)
Bài 3
a,26/100+0,009+41/100+0,24
0,26+0,09+0,41+0,24
(0,26+0,24)+(0,09+0,41)
0,5+0,5
=1
b,9+1/4+6+2/7+7+3/5+8+2/3+2/5+1/3+5/7+3/4
(9+6+7+8)+(2/7+5/7)+(1/4+3/4)+(3/5+2/5)+(2/3+1/3)
30+1+1+1+1
=34
Bài 4,5 khó quá mik ko bít lamf^^))
Bài 4: a, \(\dfrac{2008}{2009}\) < 1; \(\dfrac{10}{9}\) > 1
\(\dfrac{2008}{2009}\) < \(\dfrac{10}{9}\)
b, \(\dfrac{1}{a+1}\) và \(\dfrac{1}{a-1}\)
Ta có: a + 1 > a - 1 ⇒ \(\dfrac{1}{a+1}\) < \(\dfrac{1}{a-1}\)
\(\dfrac{5}{13}\times\dfrac{7}{11}+\dfrac{5}{13}\times\dfrac{2}{11}+\dfrac{8}{13}\times\dfrac{9}{11}\)
\(=\dfrac{5}{13}\times\left(\dfrac{7}{11}+\dfrac{2}{11}\right)+\dfrac{8}{13}\times\dfrac{9}{11}\)
\(=\dfrac{5}{13}\times\dfrac{9}{11}+\dfrac{8}{13}\times\dfrac{9}{11}\)
\(=\dfrac{9}{11}\times\left(\dfrac{5}{13}+\dfrac{8}{13}\right)\)
\(=\dfrac{9}{11}\times1\)
\(=\dfrac{9}{11}\)
a) \(20,23\times21+20,23\times80-20,23\)
\(=20,23\times\left(21+80-1\right)\)
\(=20,23\times100\)
\(=2023\)
AI lấy đêf kiểm tra toán giữa kì 1 không
ai nhanh thì mình sẽ cho
\(\frac{8}{13}+\frac{4}{9}+\frac{1}{3}+\frac{5}{13}+3\)
\(=\left(\frac{8}{13}+\frac{5}{13}\right)+\left(\frac{4}{9}+\frac{1}{3}\right)+3\)
\(=1+\frac{7}{9}+3\)
\(=\frac{43}{9}\)
a)\(\frac{8}{13}+\frac{4}{9}+\frac{1}{3}+\frac{5}{13}+\)\(3\)
\(=\left(\frac{8}{13}+\frac{5}{13}\right)+\left(\frac{4}{9}+\frac{1}{3}\right)+3\)
\(=\frac{13}{13}+\frac{7}{9}+3\)
\(=1+\frac{4}{9}+3\)
\(=4\frac{4}{9}\)
b)\(\frac{8}{5}\)X\(\frac{4}{7}+\frac{4}{7}\)X\(\frac{2}{5}-1\)
\(=\left(\frac{8}{5}+\frac{2}{5}\right)\)X\(\frac{4}{7}-1\)
\(=1\)X\(\frac{4}{7}-1\)
\(=\frac{3}{7}\)
\(\dfrac{8}{13}+\dfrac{4}{9}+\dfrac{1}{3}+\dfrac{5}{13}+3\)
\(=1+\dfrac{7}{9}+3\)
\(=4+\dfrac{7}{9}=\dfrac{43}{9}\)
cảm ơn bạn nhìu nhưng...
còn phần b thì sao bạn