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21 tháng 10 2023

a) 1 + 1/4 + 1/8 + 1/16

= 16/16 + 4/16 + 2/16 + 1/16

= 23/16

b) 2 - 1/8 - 1/12 - 1/16

= 96/48 - 6/46 - 4/48 - 3/48

= 83/48

c) 4/99 × 18/5 : 12/11 + 3/5

= 8/55 : 12/11 + 3/5

= 2/15 + 3/5

= 2/15 + 9/15

= 11/15

d) (1 - 3/4) × (1 + 1/3) : (1 - 1/3)

= 1/4 × 4/3 : 2/3

= 1/3 : 2/3

= 2

21 tháng 10 2023

1 + 1/4 + 1/8 + 1/16

= 16 + 4 + 2 + 1 / 16

=23/16

2-1/8-1/12-1/16

= 96 - 6 - 4 - 3 / 48

= 83 / 48

4/99 x 18/5 : 12 /11 + 3/5

= 4/99 x 18/5 x 11/12 + 3/5

= 2/15 + 3/5

= 11/15

(1 - 3/4) x (1+1/3) : (1-1/3) 

= 1/4 x 4/3 : 2/3

= 1/4 x 4/3 x 3/2

= 1/2

a) \(1+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}\)

\(=\frac{16}{16}+\frac{4}{16}+\frac{2}{16}+\frac{1}{16}\)

\(=\frac{23}{16}\)

b) \(2-\frac{1}{8}-\frac{1}{12}-\frac{1}{16}\)

\(=\frac{96}{48}-\frac{6}{48}-\frac{4}{48}-\frac{3}{48}\)

\(=\frac{83}{48}\)

c) \(\frac{4}{99}\cdot\frac{18}{5}\div\frac{12}{11}+\frac{3}{5}\)

\(=\frac{4\cdot18\cdot11}{99\cdot5\cdot12}+\frac{3}{5}\)

\(=\frac{4\cdot9\cdot2\cdot11}{9\cdot11\cdot5\cdot4\cdot3}+\frac{3\cdot3}{3\cdot5}\)

\(=\frac{2}{15}+\frac{9}{15}=\frac{11}{15}\)

d) \(\left(1-\frac{3}{4}\right)\left(1+\frac{1}{3}\right)\div\left(1-\frac{1}{3}\right)\)

\(=\frac{1}{4}\cdot\frac{4}{3}\div\frac{2}{3}\)

\(=\frac{1\cdot4\cdot3}{4\cdot3\cdot2}=\frac{1}{2}\)

17 tháng 10 2020

cảm s ơn bạn

 
18 tháng 10 2023

\(1+\dfrac{1}{4}+\dfrac{1}{8}+\dfrac{1}{16}\)

\(=\dfrac{5}{4}+\dfrac{1}{8}+\dfrac{1}{16}\)

\(=\dfrac{11}{8}+\dfrac{1}{16}\)

\(=\dfrac{23}{16}\)

______

\(2-\dfrac{1}{8}-\dfrac{1}{12}-\dfrac{1}{16}\)

\(=\dfrac{15}{8}-\dfrac{1}{12}-\dfrac{1}{16}\)

\(=\dfrac{43}{24}-\dfrac{1}{16}\)

\(=\dfrac{83}{48}\)

_________

\(\dfrac{4}{99}\times\dfrac{18}{5}:\dfrac{12}{11}+\dfrac{3}{5}\)

\(=\dfrac{8}{55}:\dfrac{12}{11}+\dfrac{3}{5}\)

\(=\dfrac{8}{55}\times\dfrac{11}{12}+\dfrac{3}{5}\)

\(=\dfrac{2}{15}+\dfrac{3}{5}\)

\(=\dfrac{11}{15}\)

__________

\(\left(1-\dfrac{3}{4}\right)\times\left(1+\dfrac{1}{3}\right)\times\left(1-\dfrac{1}{3}\right)\)

\(=\dfrac{1}{4}\times\dfrac{4}{3}\times\dfrac{2}{3}\)

\(=\dfrac{4\times2}{4\times3\times3}\)

\(=\dfrac{2}{3\times3}\)

\(=\dfrac{2}{9}\)

17 tháng 10 2020

a] 23/16

c)7/45

d)1/2

b)83/48

Đúng nhé mình làm tong toán nâng cao lớp 5 rồi

7 tháng 8 2016

các cậu trả lời giúp mình đi

\(a,\frac{2}{3}+\frac{1}{2}+\frac{1}{6}=\frac{4}{6}+\frac{3}{6}+\frac{1}{6}=\frac{8}{6}=\frac{4}{3}\)

\(b,\frac{5}{12}+\frac{5}{6}-\frac{3}{4}=\frac{5}{12}+\frac{10}{12}-\frac{9}{12}=\frac{6}{12}=\frac{1}{2}\)

a) 2/3 + 1/2 + 1/6 =  4/6 + 3/6 +  1/6 = 7/6 + 1/6 = 8/6 = 4/3 

 b) 5/12 + 5/6 - 3/4 = 5/12 + 10/12 - 9/12 = 15/12 - 9/12 = 6/12 = 1/2

 c) 1/3 x 3/5 x 2/5 = 3/15 x 2/5 = 6/75  = 2/25

 d) 15/16 : 3/8 x 3/4 = 15/16 x 8/3 x 3/4 = 1/10 x 3/4 = 3/40 

3 tháng 8 2016

a.1+3+5+7+9+11+13+15+17+19

muốn tính tổng của dãy ta lấy tổng số đầu và cuối nhân số các số hạng rồi chia 2.

tổng của dãy:(19+1)x10:2=100

    

28 tháng 7 2023

a) \(2+\dfrac{3}{4}\)

\(=\dfrac{8}{4}+\dfrac{3}{4}\)

\(=\dfrac{8+3}{4}\)

\(=\dfrac{11}{4}\)

b) \(\dfrac{1}{3}+\dfrac{3}{2}-\dfrac{7}{4}\)

\(=\dfrac{4}{12}+\dfrac{18}{12}-\dfrac{21}{12}\)

\(=\dfrac{4+18-21}{12}\)

\(=\dfrac{1}{12}\)

c) \(\dfrac{1}{6}+\dfrac{3}{8}-\dfrac{1}{4}\)

\(=\dfrac{4}{24}+\dfrac{9}{24}-\dfrac{6}{24}\)

\(=\dfrac{4+9-6}{24}\)

\(=\dfrac{7}{24}\)

d) \(\dfrac{5}{12}+\dfrac{3}{8}\times\dfrac{4}{9}\)

\(=\dfrac{5}{12}+\dfrac{3\times4}{8\times9}\)

\(=\dfrac{5}{12}+\dfrac{1}{6}\)

\(=\dfrac{5}{12}+\dfrac{2}{12}\)

\(=\dfrac{7}{12}\)

e) \(\dfrac{4}{5}-\dfrac{1}{5}\times\dfrac{7}{2}\)

\(=\dfrac{4}{5}-\dfrac{1\times7}{5\times2}\)

\(=\dfrac{4}{5}-\dfrac{7}{10}\)

\(=\dfrac{8}{10}-\dfrac{7}{10}\)

\(=\dfrac{8-7}{10}\)

\(=\dfrac{1}{10}\)

f) \(\dfrac{16}{9}-\dfrac{4}{15}:\dfrac{2}{5}\)

\(=\dfrac{16}{9}-\dfrac{4}{15}\times\dfrac{5}{2}\)

\(=\dfrac{16}{9}-\dfrac{4\times5}{15\times2}\)

\(=\dfrac{16}{9}-\dfrac{2}{3}\)

\(=\dfrac{16}{9}-\dfrac{6}{9}\)

\(=\dfrac{16-6}{9}\)

\(=\dfrac{10}{9}\)

a: =8/4+3/4=11/4

b: =4/12+18/12-21/12=1/12

c: =4/24+9/24-6/24=7/24

d: =5/12+12/72

=5/12+1/6

=5/12+2/12=7/12

e: =4/5-7/10

=8/10-7/10=1/10

f: =16/9-4/15*5/2

=16/9-20/30

=16/9-2/3

=16/9-6/9=10/9