Tính rồi rút gọn(nếu có thể):
a/ ( 2 - 2/17 ) x 51/64
b/ ( 2/5 + 5/7 ) x 5/13
c/ 13/18 : ( 7/12 - 4/9 )
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Tính rồi rút gọn(nếu có thể):
a/ ( 2 - 2/17 ) x 51/64
b/ ( 2/5 + 5/7 ) x 5/13
c/ 13/18 : ( 7/12 - 4/9 )
a. \(\left(2-\frac{2}{17}\right)\times\frac{51}{64}\)
\(=\frac{22}{17}\times\frac{51}{64}\)
\(=\frac{22\times51}{17\times64}=\frac{1122}{1088}=\frac{561}{544}\)
b. \(\left(\frac{2}{5}+\frac{5}{7}\right)\times\frac{5}{13}\)
\(=\frac{39}{35}\times\frac{5}{13}\)
\(=\frac{3}{7}\)
c. \(\frac{13}{18}\div\left(\frac{7}{12}-\frac{4}{9}\right)\)
\(=\frac{13}{18}\div\frac{28}{27}\)
\(=\frac{13}{18}\times\frac{27}{28}=\frac{39}{56}\)
#z
\(\left(2-\frac{2}{17}\right)\times\frac{51}{64}\)
\(=\frac{32}{17}\times\frac{51}{64}\)
\(=\frac{1632}{1088}=\frac{3}{2}\)
\(\left(\frac{2}{5}+\frac{5}{7}\right)\times\frac{5}{13}\)
\(=\left(\frac{14}{35}+\frac{25}{35}\right)\times\frac{5}{13}\)
\(=\frac{39}{35}\times\frac{5}{13}\)
\(=\frac{195}{455}=\frac{3}{7}\)
\(\frac{13}{18}:\left(\frac{7}{12}-\frac{4}{9}\right)\)
\(=\frac{13}{18}:\left(\frac{63}{108}-\frac{48}{108}\right)\)
\(=\frac{13}{18}:\frac{5}{36}\)
\(=\frac{13}{18}\times\frac{36}{5}\)
\(=\frac{468}{90}=\frac{26}{5}\)
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
BÀI 1:
a) \(\frac{4}{5}+\frac{3}{8}+\frac{1}{4}\)
\(=\frac{32}{40}+\frac{15}{40}+\frac{10}{40}\)
\(=\frac{32+15+10}{40}\)\(=\frac{57}{40}\)
b) \(\frac{5}{9}+\frac{2}{3}+\frac{1}{2}\)
\(=\frac{10}{18}+\frac{12}{18}+\frac{9}{18}\)
\(=\frac{10+12+9}{18}=\frac{31}{18}\)
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 =\(\frac{9}{12}:\frac{7}{9}\times\frac{12}{19}\)
= \(\frac{4}{7}\times\left(\frac{2}{5}+\frac{3}{5}\right)\) =\(\left(\frac{17}{13}-\frac{4}{13}\right)\times\frac{12}{17}\) = \((\frac{9}{14}+\frac{5}{14}):\frac{6}{7}\) = \(\frac{9}{12}\times\frac{9}{7}\times\frac{12}{19}\)
=\(\frac{4}{7}\times1\) = \(1\times\frac{12}{17}\) = \(1:\frac{6}{7}\) = \(\frac{9\times9\times12}{12\times7\times19}\)
=\(\frac{4}{7}\) = \(\frac{12}{17}\) =\(\frac{7}{6}\) = \(\frac{9\times9}{7\times19}=\frac{81}{133}\)
\(\frac{5}{7}-\frac{4}{17}=\frac{5}{7}-\frac{2}{8,5}=\frac{42,5}{59,5}-\frac{14}{59,5}=\frac{38,5}{59,5}\)
\(\frac{21}{27}-\frac{2}{9}=\frac{7}{9}-\frac{2}{9}=\frac{5}{9}\)
\(\frac{13}{5}-\frac{35}{25}=\frac{13}{5}-\frac{7}{5}=\frac{6}{5}\)
bài 4:so sánh
5/2 lớn hơn 3/7
4/3 lớn hơn,3/2 lớn hơn
bài 6:rút gọn các phân số sau:
3/9=1/3 9/12=3/4 8/18=4/9 60/36=10/6 17/34=1/2 17/51=1/3 35/100=7/20 25/100=1/4 8/1000=1/125 24/30=4/5 18/54=1/3 72/42=12/7
đay nhé mk chưa làm hết đc bn viết liền quá mk nhìn khó mà mk hỏi bài 7 là nhân hay cộng vậy?