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a) = 17/19 - 17/19 + 27/35 + 35/35 = 0 + 62/35
b) = 1/3 x 4/5 + 1/3 x6/5 + 1/3 x 2 = 1/3(4/5 + 6/5 + 2) = 1/3 x 4 = = 4/3
c) 4/7 x 2/9 + 4/7 x 7/9 + 2/3 = 4/7 x (2/9 + 7/9) + 2/3 = 4/7 x 1 + 2/3 = 26/21
A) 17/19 - 17/19 + 27/35 + 35/35 = 0 + 62/35
B) 1/3 x 4/5 + 1/3 x 6/5 + 1/3 x 2 = 1/3 x(4/5 + 6/5 x 2 ) = 1/3 x 4 = 4/3
c) TƯƠNG TỰ CÂU A VÀ B
* HOKTOT*
NHA
1: Tìm x:
a) \(X-\frac{1}{2}=3\frac{1}{2}\)
\(X-\frac{1}{2}=\frac{7}{2}\)
\(X=\frac{7}{2}+\frac{1}{2}\)
\(X=\frac{8}{2}\)
\(X=4\)
b) \(9\frac{1}{2}-x=3\frac{1}{4}\)
\(\frac{19}{2}-x=\frac{13}{4}\)
\(x=\frac{19}{2}-\frac{13}{4}\)
\(x=\frac{38}{4}-\frac{13}{4}\)
\(x=\frac{25}{4}\)
c) \(\left(\frac{7}{8}-x\right)+\frac{1}{8}=\frac{1}{4}\)
\(\frac{7}{8}-x=\frac{1}{4}-\frac{1}{8}\)
\(\frac{7}{8}-x=\frac{2}{8}-\frac{1}{8}\)
\(\frac{7}{8}-x=\frac{1}{8}\)
\(x=\frac{7}{8}-\frac{1}{8}\)
\(x=\frac{6}{8}\)
\(x=\frac{3}{4}\)
d) \(x-\frac{1}{2}:\frac{1}{6}=\frac{3}{4}\)
\(x-\frac{1}{2}x6\)= \(\frac{3}{4}\)
\(x-\frac{6}{2}=\frac{3}{4}\)
\(x=\frac{3}{4}+\frac{6}{2}\)
\(x=\frac{3}{4}+\frac{12}{4}\)
\(x=\frac{15}{4}\)
2: Nửa chu vi hình chữ nhật là:
96 : 2 = 48 ( cm )
Chiều dài của hình chữ nhật là:
48 : ( 2 + 1 ) x 2 = 32 ( cm )
Chiều rộng hình chữ nhật là:
48 - 32 = 16 ( cm )
Diện tích hình chữ nhật đó là:
32 x 16 = 512 ( cm2 )
Đ/S: 512 cm2
a) \(\frac{7}{8}\) - \(\frac{1}{3}\) = \(\frac{21}{24}\) - \(\frac{8}{24}\) = \(\frac{13}{24}\)
\(\frac{8}{9}\) + \(\frac{2}{5}\) = \(\frac{40}{45}\) + \(\frac{18}{45}\) = \(\frac{58}{45}\)
\(\frac{3}{10}\) x \(\frac{1}{6}\) = \(\frac{3\times1}{10\times6}\) = \(\frac{3}{60}\) = \(\frac{1}{20}\)
\(\frac{8}{9}\) : \(\frac{3}{7}\) = \(\frac{8}{9}\) x \(\frac{7}{3}\) = \(\frac{56}{27}\)
b) Đổi hỗn số ra phân số rồi làm tương tự câu a)
a.7,2 :2 x 58,6 + 2,93 x 2 x 64
= 3,6 x 58,6 + 5,86 x 64
=210,96 + 357,04
=586
b.\(4\frac{2}{5}+2\frac{3}{7}-2\frac{2}{5}+5\frac{4}{7}\)
=\(\left(4\frac{2}{5}-2\frac{2}{5}\right)+\left(2\frac{3}{7}+5\frac{4}{7}\right)\)
= 2 + 8
= 10
c. 2 x 41 x 36 + 8 x 9 x 58 + 12 x 6
=72 x 41 + 72 x 58 + 72 x 1
=72 x ( 41 + 58 +1 )
=72 x 100
=7200
d, \(\frac{3}{5}\)x \(\frac{1}{2}\):\(\frac{2}{5}\)
=\(\frac{3}{5}\)x \(\frac{1}{2}\)x\(\frac{5}{2}\)
=\(\frac{3}{4}\)
\(9\frac{1}{4}+6\frac{2}{7}+7\frac{3}{5}+8\frac{2}{3}+\frac{2}{5}+\frac{1}{3}+\frac{5}{7}+\frac{3}{4}\)
\(=\left(9\frac{1}{4}+\frac{3}{4}\right)+\left(6\frac{2}{7}+\frac{5}{7}\right)+\left(7\frac{3}{5}+\frac{2}{5}\right)+\left(8\frac{2}{3}+\frac{1}{3}\right)\)
\(=\left(\frac{37}{4}+\frac{3}{4}\right)+\left(\frac{44}{7}+\frac{5}{7}\right)+\left(\frac{38}{5}+\frac{2}{5}\right)+\left(\frac{26}{3}+\frac{1}{3}\right)\)
\(=\frac{40}{4}+\frac{49}{7}+\frac{40}{5}+\frac{40}{5}+\frac{27}{3}\)
\(=10+7+8+8+9\)
\(=42\)
**** nha Bùi Xuân Lê
câu 1 = 0
câu 2 : X=\(\frac{16}{105}\)
X =\(\frac{180}{77}\)
X = 63
(18\(\dfrac{1}{2}+5\dfrac{3}{8}-7\dfrac{5}{24}\)) - 16\(\dfrac{2}{3}\)
=( \(\dfrac{37}{2}\) + \(\dfrac{43}{8}\) - \(\dfrac{171}{24}\) ) - \(\dfrac{50}{3}\)
= \(\dfrac{50}{3}\) - \(\dfrac{50}{3}\)
=0
19/8+5/4-27/7-233/56
29/8-27/7-233/56
202/56-10216/56-233/56
-14/56-233/56
-247/56
Bài làm
\(2\frac{3}{8}+1\frac{1}{4}+3\frac{6}{7}-4\frac{9}{56}\)
\(=\frac{19}{8}+\frac{5}{4}+\frac{27}{7}-\frac{233}{56}\)
\(=\frac{133}{56}+\frac{70}{56}+\frac{216}{56}-\frac{233}{56}\)
\(=\frac{186}{56}\)
\(=\frac{93}{28}\)
\(8\dfrac{1}{9}\times1\dfrac{1}{7}=\dfrac{8\times9+1}{9}\times\dfrac{1\times7+1}{7}\)
\(=\dfrac{73}{9}\times\dfrac{8}{7}=\dfrac{584}{63}\)
8 1/9 . 1 1/7
=73/9 .8/7
= 584/63