Tính nhanh:a)M=$\frac{5}{2}$ $\frac{5}{6}$ $\frac{5}{12}$ $\frac{5}{20}$ ......... $\frac{5}{9900}$b)Q=$\frac{1}{3}$ $\frac{1}{6}$ $\frac{1}{10}$ ......... \(\frac{1}{4950}...

TT

Trương Thanh Nhân

23 tháng 5 2019

M=$5\left(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+...+\frac{1}{99}-\frac{1}{100}\right)=5\left(1-\frac{1}{100}\right)=5.\frac{99}{100}=\frac{99}{20}$

NH

Nguyễn Hà Phương

11 tháng 5 2015

$A=\frac{7}{6}+\frac{13}{12}+\frac{21}{20}+\frac{31}{30}+...+\frac{9901}{9900}$

$B=\frac{2}{3}+\frac{5}{6}+\frac{9}{10}+\frac{14}{15}+...+\frac{4949}{4950}$

1

SN

✓ ℍɠŞ_ŦƦùM $₦G ✓

11 tháng 5 2015

$A=\frac{7}{6}+\frac{13}{12}+\frac{21}{20}+...+\frac{9901}{9900}=\left(1+\frac{1}{2.3}\right)+\left(1+\frac{1}{3.4}\right)+\left(1+\frac{1}{4.5}\right)+...+\left(1+\frac{1}{99.100}\right)$$=\left(1+1+1+...+1\right)+\left(\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+...+\frac{1}{99.100}\right)$

$=98+\left(\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+...+\frac{1}{99}-\frac{1}{100}\right)=98+\left(\frac{1}{2}-\frac{1}{100}\right)$

$=98+\frac{49}{100}=98\frac{49}{100}$

DG

Duy Gaming Youtube

2 tháng 9 2020

a) $\frac{5}{12}+\frac{5}{20}+\frac{5}{30}+...+\frac{5}{9900}$

b) $\frac{5}{6}+\frac{11}{12}+\frac{19}{20}+...+\frac{89}{90}$

c) $\frac{7}{6}+\frac{13}{12}+\frac{21}{20}+...+\frac{91}{90}$

d) $\left(6-\frac{2}{3}+\frac{1}{2}\right)-\left(5+\frac{5}{3}-\frac{2}{3}\right)-\left(3-\frac{7}{3}+\frac{5}{2}\right)$

3

DG

Duy Gaming Youtube

2 tháng 9 2020

Mấy câu như này tách ra kiểu gì?

T

Thảo

2 tháng 9 2020

$\frac{5}{12}+\frac{5}{20}+\frac{5}{30}+...+\frac{5}{9900}=\frac{5}{3.4}+\frac{5}{4.5}+\frac{5}{5.6}+...+\frac{5}{99.100}$

$5\left(\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}+...+\frac{1}{99}-\frac{1}{100}\right)$

$5\left(\frac{1}{3}-\frac{1}{100}\right)=\frac{97}{60}$

DJ

Đông joker

25 tháng 5 2016

A=1+2+3+4+5+...+99+100

B=$\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+\frac{1}{30}+...+\frac{1}{9900}$

9

SB

soyeon_Tiểu bàng giải

25 tháng 5 2016

A=1+2+3+4+5+...+99+100

A=(1+100).100:2=101.50=5050

B=1/2+1/6+1/12+1/20+1/30+...+1/9900

B=1/1.2+1/2.3+1/3.4+1/4.5+1/5.6+....+1/99.100

B=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+...+1/99-1/100

B=1-1/100=99/100

LD

l҉o҉n҉g҉ d҉z҉

25 tháng 5 2016

A = 100 x 101 : 2 = 5050

$B=\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+.........+\frac{1}{99.100}$

$=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+.....+\frac{1}{99}-\frac{1}{100}$

$=1-\frac{1}{100}$

$=\frac{99}{100}$

HH

Hà Huy Hoàng

10 tháng 7 2018

Bài 1: Tính K =$\frac{10}{56}+\frac{10}{140}+\frac{10}{260}$+...+$\frac{10}{1400}$

Bài 2: Cho M =$\frac{1}{2}+\frac{1}{12}+\frac{1}{30}+...+\frac{1}{9900}$.CMR: M<$\frac{5}{6}$.

0

NC

Nguyễn Châu Mỹ Linh

20 tháng 6 2018

...

Đọc tiếp

$\left(\frac{-5}{12}+\frac{7}{4}-\frac{3}{8}\right)-\left[4\frac{1}{2}-7\frac{1}{3}\right]-\left(\frac{1}{4}-\frac{5}{2}\right)$

$\left[2\frac{1}{4}-5\frac{3}{2}\right]-\left(\frac{3}{10}-1\right)-5\frac{1}{2}+\left(\frac{1}{3}-\frac{5}{6}\right)$

$\frac{4}{7}-\left(3\frac{2}{5}-1\frac{1}{2}\right)-\frac{5}{21}+\left[3\frac{1}{2}-4\frac{2}{3}\right]$

$\frac{1}{8}-1\frac{3}{4}+\left(\frac{7}{8}-3\frac{7}{2}+\frac{3}{4}\right)-\left[\frac{7}{4}-\frac{5}{8}\right]$

$\left(\frac{3}{5}-2\frac{1}{10}+\frac{11}{20}\right)-\left[\frac{-3}{4}+1\frac{7}{2}\right]$

$\left[-2\frac{1}{5}-2\frac{2}{3}\right]-\left(\frac{1}{15}-5\frac{1}{2}\right)+\left[\frac{-1}{6}+\frac{1}{3}\right]$

$1\frac{1}{8}-\left(\frac{1}{15}-\frac{1}{2}+\frac{-1}{6}\right)+\left[\frac{5}{4}+\frac{3}{2}\right]$

$\frac{5}{6}-\left(1\frac{1}{3}-1\frac{1}{2}\right)+\left[\frac{5}{12}-\frac{3}{4}-\frac{1}{6}\right]$

$1\frac{1}{4}-\left(\frac{7}{12}-\frac{2}{3}-1\frac{3}{8}\right)+\left[\frac{5}{24}-2\frac{1}{2}\right]-\frac{1}{6}-\left[\frac{-3}{4}\right]$

$-2\frac{1}{5}+2\frac{3}{10}-\left(\frac{6}{20}-\left[\frac{2}{8}-1\frac{1}{2}\right]\right)+\left[\frac{7}{20}-1\frac{1}{4}\right]$

$-\left[1\frac{2}{3}-3\frac{1}{2}+\frac{1}{4}\right]+\left(\frac{2}{6}-\frac{5}{12}\right)-\left(\frac{1}{3}-\left[\frac{1}{4}-\frac{1}{3}\right]\right)$

$-\frac{4}{5}-\left(1\frac{1}{10}-\frac{7}{10}\right)+\left[\frac{3}{4}-1\frac{1}{5}\right]+1\frac{1}{2}$

$\frac{3}{21}-\frac{5}{14}+\left[1\frac{1}{3}-5\frac{1}{2}+\frac{5}{14}\right]-\left(\frac{1}{6}-\frac{3}{7}+\frac{1}{3}\right)$

$-1\frac{2}{5}+\left[1\frac{3}{10}-\frac{7}{20}-1\frac{1}{4}\right]-\left(\frac{1}{5}-\left[\frac{3}{4}-1\frac{1}{2}\right]\right)$

$2\frac{1}{3}-\left(\frac{1}{2}-2\frac{1}{6}+\frac{3}{4}\right)+\left[\frac{5}{12}-1\frac{1}{3}\right]-\frac{7}{8}+3\frac{1}{2}$

$2\frac{1}{4}-1\frac{3}{5}-\left(\frac{9}{20}-\frac{7}{10}\right)+\left[1\frac{3}{5}-2\frac{1}{2}\right]+\frac{3}{4}$

$\left[\frac{8}{3}-5\frac{1}{4}+\frac{1}{6}\right]-\frac{7}{4}+\frac{-5}{12}-\left(1-1\frac{1}{2}+\frac{1}{3}\right)$

$\left(\frac{1}{4}-\left[1\frac{1}{4}-\frac{7}{10}\right]+\frac{1}{2}\right)-2\frac{1}{5}-1\frac{3}{10}+\left[1-\frac{1}{2}\right]$

TRÌNH BÀY GIÚP MÌNH NHA

Bài 1 :Thực hiện phép tính : a) M =($\frac{-6}{13}+\frac{15}{26}-\frac{47}{39}-\frac{1}{78}$) : ($99\frac{17}{65}-100\frac{5}{52}+\frac{1}{130}$) b) N = $\frac{(\frac{3}{5}-0,435+\frac{1}{200}):\left(-0,04\right)}{30,75+\frac{1}{12}+3\frac{1}{6}}$ c) P = ($\frac{-5}{6}:\frac{-10}{11}$)+$\frac{\frac{1}{4}+\frac{5}{8}-\frac{7}{13}}{\frac{-2}{12}-\frac{10}{24}+\frac{14}{39}}$ Bài 2 : Thực hiện phép tính :V a) P...

0

MM

Minh Minh

26 tháng 11 2019

Đọc tiếp

1

NH

nguyen hong long

26 tháng 11 2019

có rất nhiều câu dễ ở trong đề sao bạn Ko thử làm đi rồi câu nào khó lại hỏi

MM

Minh Minh

27 tháng 11 2019

vậy bạn thấy câu nào khó thì làm giúp với :V

TT

Trần Trung Kiên

20 tháng 7 2016

Tính

a)B=$\frac{1+2+2^2+2^3+...+2^{2008}}{1-2^{2009}}$

b)A=1+2+3+4+5+...+99+100

B=$\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+\frac{1}{30}+...+\frac{1}{9900}$

0

TV

Trần Văn Quyết

27 tháng 4 2017

Tìm x : $\frac{6:\frac{3}{5}-1\frac{1}{16}\cdot\frac{6}{7}}{4\frac{1}{5}\cdot\frac{10}{11}+5\frac{2}{11}}$$-\frac{\left(\frac{3}{20}+\frac{1}{2}-\frac{1}{5}\right)\cdot\frac{12}{49}}{3\frac{1}{3}+\frac{2}{9}}$

0

HK

Hikariga Kyoka

1 tháng 8 2020

Tính giá trị biểu thức
2) K= $\frac{1}{6}$+$\frac{1}{12}$+$\frac{1}{20}$+...+ $\frac{1}{9900}$

3) L= $\frac{5}{1.4}$+$\frac{5}{4.7}$+ .... + $\frac{5}{100.103}$

6

NT

Nguyễn Trọng Vũ Hùng

1 tháng 8 2020

$\left(2\right)K=\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+...+\frac{1}{9900}$

$K=\frac{1}{2\cdot3}+\frac{1}{3\cdot4}+\frac{1}{4\cdot5}+...+\frac{1}{99\cdot100}$

$K=\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+...+\frac{1}{99}-\frac{1}{100}$

$K=\frac{1}{2}-\frac{1}{100}=\frac{49}{100}$

$\left(3\right)L=\frac{5}{1\cdot4}+\frac{5}{4\cdot7}+\frac{5}{7\cdot10}+...+\frac{5}{100\cdot103}$

$L=\frac{5}{3}\cdot\left(\frac{1}{1}-\frac{1}{4}+\frac{1}{4}-\frac{1}{7}+\frac{1}{7}-\frac{1}{10}+...+\frac{1}{100}-\frac{1}{103}\right)$

$L=\frac{5}{3}\cdot\left(\frac{1}{1}-\frac{1}{103}\right)=\frac{5}{3}\cdot\frac{102}{103}=\frac{510}{309}=\frac{170}{103}$

KA

Kiyotaka Ayanokoji

1 tháng 8 2020

Trả lời:

2,$K=\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+...+\frac{1}{9900}$

$K=\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+...+\frac{1}{99.100}$

$K=\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+...+\frac{1}{99}-\frac{1}{100}$

$K=\frac{1}{2}-\frac{1}{100}$

$K=\frac{49}{100}$

3,$L=\frac{5}{1.4}+\frac{5}{4.7}+...+\frac{5}{100.103}$

$L=\frac{5}{3}\times\left(\frac{3}{1.4}+\frac{3}{4.7}+...+\frac{3}{100.103}\right)$

$L=\frac{5}{3}\times\left(\frac{1}{1}-\frac{1}{4}+\frac{1}{4}-\frac{1}{7}+...+\frac{1}{100}-\frac{1}{103}\right)$

$L=\frac{5}{3}\times\left(\frac{1}{1}-\frac{1}{103}\right)$

$L=\frac{5}{3}\times\frac{102}{103}$

$L=\frac{170}{103}$

Học tốt