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29 tháng 5 2023

  16\(\dfrac{1}{2}\) - 6,5 \(\times\) 75% + \(\dfrac{1}{4}\) \(\times\) 6,5

= 16 + 0,5 - 6,5 \(\times\) 7,5 + 0,25 \(\times\) 6,5

= 16 + 0,5 - 6,5 \(\times\) ( 0,75 - 0,25)

= 16 + 0,5 - 6,5 \(\times\) 0,5

= 16,5 - 3,25

= 13,25

AH
Akai Haruma
Giáo viên
29 tháng 5 2023

Dấu nối giữa 16 và 1/2 là gì vậy bạn?

19 tháng 9 2023

` 242/363 + 1616/2121 = 2/7 xxy`

`2/7 xxy= 2/3 + 16/21`

`2/7 xxy= 14/21 +16/21`

`2/7 xxy= 30/21`

`y=10/7 : 2/7`

`y=10/7 xx 7/2`

`y=70/14`

`y=5`

__

` (y + 1/4) + (y + 1/16) + (y + 1/16) =2`

`(y+y+y)+(1/4 + 1/16+1/16)=2`

`3y + (4/16 +1/16 +1/16)=2`

`3y + 6/16=2`

`3y=2-6/16`

`3y= 32/16-6/16`

`3y= 26/16`

`y=26/16 : 3`

`y=26/48`

`y=13/24`

 

19 tháng 9 2023

\(a,\dfrac{242}{363}+\dfrac{1616}{2121}=\dfrac{2}{7}\times y\)

\(\dfrac{2}{7}\times y=\dfrac{2\times121}{3\times121}+\dfrac{16\times101}{21\times101}\)

\(\dfrac{2}{7}\times y=\dfrac{2}{3}+\dfrac{16}{21}\)

\(\dfrac{2}{7}\times y=\dfrac{14}{21}+\dfrac{16}{21}\)

\(\dfrac{2}{7}\times y=\dfrac{30}{21}\)

\(\dfrac{2}{7}\times y=\dfrac{10}{7}\)

\(y=\dfrac{10}{7}:\dfrac{2}{7}\)

\(y=\dfrac{10}{7}\times\dfrac{7}{2}\)

\(y=5\)

\(---\)

\(b,\left(y+\dfrac{1}{4}\right)+\left(y+\dfrac{1}{16}\right)+\left(y+\dfrac{1}{16}\right)=2\)

\(\left(y+y+y\right)+\left(\dfrac{1}{4}+\dfrac{1}{16}+\dfrac{1}{16}\right)=2\)

\(3\times y+\left(\dfrac{4}{16}+\dfrac{2}{16}\right)=2\)

\(3\times y+\dfrac{6}{16}=2\)

\(3\times y+\dfrac{3}{8}=2\)

\(3\times y=2-\dfrac{3}{8}\)

\(3\times y=\dfrac{16}{8}-\dfrac{3}{8}\)

\(3\times y=\dfrac{13}{8}\)

\(y=\dfrac{13}{8}:3\)

\(y=\dfrac{13}{8}\times\dfrac{1}{3}\)

\(y=\dfrac{13}{24}\)

#\(Toru\)

DD
3 tháng 6 2021

\(A=\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}+\frac{1}{32}+\frac{1}{64}+\frac{1}{128}\)

\(2\times A=1+\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}+\frac{1}{32}+\frac{1}{64}\)

\(2\times A-A=\left(1+\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}+\frac{1}{32}+\frac{1}{64}\right)-\left(\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}+\frac{1}{32}+\frac{1}{64}+\frac{1}{128}\right)\)

\(A=1-\frac{1}{128}\)

\(A=\frac{127}{128}\)

DD
3 tháng 6 2021

\(B=\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}\)

\(2\times B=1+\frac{1}{2}+\frac{1}{4}+\frac{1}{8}\)

\(B=1-\frac{1}{16}=\frac{15}{16}\)

\(\left(x+\frac{1}{2}\right)+\left(x+\frac{1}{4}\right)+\left(x+\frac{1}{8}\right)+\left(x+\frac{1}{16}\right)=1\)

\(\Leftrightarrow4\times x+\frac{15}{16}=1\)

\(\Leftrightarrow4\times x=\frac{1}{16}\)

\(\Leftrightarrow x=\frac{1}{64}\)

1+\(\frac{1}{4}\)+\(\frac{1}{8}\)+\(\frac{1}{16}\)=\(\frac{23}{16}\)

2__\(\frac{1}{8}\)__\(\frac{1}{12}\)__\(\frac{1}{16}\)=\(\frac{83}{48}\)

1 + 1/4 + 1/8 + 1/16 = 1,4375

phép tính thứ hai thì chịu

28 tháng 10 2017

1-2-3-4-...-1 0000...0 hơi sai sai. Số bé làm sao trừ được số lớn, lớp 5 cũng chưa học số âm?

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

18 tháng 10 2023

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

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

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

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

______

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

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

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

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

_________

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

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

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

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

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

__________

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

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

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

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

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

29 tháng 4 2018

Trả lời

\(\left(x+\frac{1}{2}\right)+\left(x+\frac{1}{4}\right)+\left(x+\frac{1}{8}\right)+\left(x+\frac{1}{16}\right)=\frac{23}{16}\)

\(\Leftrightarrow\left(x+x+x+x\right)+\left(\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}\right)=\frac{23}{16}\)

\(\Leftrightarrow4x+\left(\frac{8}{16}+\frac{4}{16}+\frac{2}{16}+\frac{1}{16}\right)=\frac{23}{16}\)

\(\Leftrightarrow4x+\frac{8+4+2+1}{16}=\frac{23}{16}\)

\(\Leftrightarrow4x+\frac{15}{16}=\frac{23}{16}\)

\(\Leftrightarrow4x=\frac{23}{16}-\frac{15}{16}\)

\(\Leftrightarrow4x=\frac{8}{16}\)

\(\Leftrightarrow4x=\frac{1}{2}\)

\(\Leftrightarrow x=\frac{1}{2}:4\)

\(\Leftrightarrow x=\frac{1}{8}\)

Vậy x=\(\frac{1}{8}\)

29 tháng 4 2018

\(\left(x+\frac{1}{2}\right)+\left(x+\frac{1}{4}\right)+\left(x+\frac{1}{8}\right)+\left(x+\frac{1}{16}\right)=\frac{23}{16}\)

\(\Leftrightarrow\left(x+x+x+x\right)+\left(\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}\right)=\frac{23}{16}\)

\(\Leftrightarrow4x+\left(\frac{8+4+2+1}{16}\right)=\frac{23}{16}\)

\(\Leftrightarrow4x+\frac{15}{16}=\frac{23}{16}\)

\(\Leftrightarrow4x=\frac{23}{16}-\frac{15}{16}\)

\(\Leftrightarrow4x=\frac{1}{2}\)

\(\Leftrightarrow x=\frac{1}{2}:4\)

\(\Leftrightarrow x=\frac{1}{8}\)

26 tháng 8 2016

\(\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+\frac{1}{20}\)

\(=\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}\)

\(=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}\)

\(=1-\frac{1}{5}\)

\(=\frac{4}{5}\)

\(\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+...+\frac{1}{9900}\)

\(=\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+...+\frac{1}{98.99}+\frac{1}{99.100}\)

\(=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+....+\frac{1}{98}-\frac{1}{99}+\frac{1}{99}-\frac{1}{100}+\frac{1}{100}\)

\(=1-\frac{1}{100}\)

\(=\frac{99}{100}\)

26 tháng 8 2016

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