`@` `\text {Ans}`

`\downarrow`

`A)`

`37 \times 46+37 \times 51+111`

`= 37 \times (46+51)+111`

`= 37 \times 97+111`

`= 3589 +111`

`= 3700`

`B)`

`35 \times 215-35 \times 210-175`

`= 35 \times (215-210)-175`

`= 35 \times 5-175`

`= 175-175=0`

`E)`

`76 \times 102-76 \times 2`

`= 76 \times (102-2)`

`= 76 \times 100`

`= 7600`

`C)`

`85 \times 94+85 \times 2 +170 \times 2`

`= 85 \times (94+2) + 170 \times 2`

`= 85 \times 96+170 \times 2`

`= 8160+340`

`= 8500`

`48 \times 56+28 \times 104`

`= 48 \times 28 \times 2+28 \times 104`

`= 28 \times (48 \times 2+104)`

`= 28 \times (96+104)`

`= 28 \times 200`

`= 5600`

`G)`

`206 \times 12-206-206`

`= 206 \times (12-1-1)`

`= 206 \times 10`

`= 2060`

a) 37 x 46 + 37 x 51 + 111

= 37 x ( 46 + 51 ) + 111

= 37 x 97 + 111

= 3589 + 111

= 3700

b) 35 x 215 - 35 x 210 - 175

= 35 x ( 215 - 210 ) - 175

= 35 x 5 - 175

= 175 - 175

= 0

e) 76 x 102 - 76 x 2

= 76 x ( 102 - 2 )

= 76 x 100

= 7600

c) 85 x 94 + 95 x 2 + 170 x 2

= 7990 + 2 x ( 95 + 170 )

= 7990 + 2 x 265

= 7990 + 530

= 8520

48 x 56 + 28 x 104

= 2688 + 2912

= 5600

g) 206 x 12 - 206 - 206

= 2472 - 206 - 206

= 2266 - 206

= 2060

1/2 . A=1/42+1/56+1/72+1/90+...+1/420

1/2 . A=1/6.7+1/7.8+1/8.9+1/9.10+...+1/20.21

1/2 .A=1/6-1/7+1/7-1/8+1/8-1/9+1/9-1/10+....+1/20-1/21

1/2 . A=1/6-1/21

1/2 .A=5/42

A=5/42:1/2

A=5/21

Chúc bạn học giỏi nhớ tick cho mình nhé

\(A=\dfrac{1}{21}+\dfrac{1}{28}+\dfrac{1}{36}+\dfrac{1}{45}+...+\dfrac{1}{210}\)

\(2.\left(\dfrac{1}{42}+\dfrac{1}{56}+\dfrac{1}{72}+\dfrac{1}{90}+...+\dfrac{1}{420}\right)\)

\(2.\left(\dfrac{1}{6.7}+\dfrac{1}{7.8}+\dfrac{1}{8.9}+\dfrac{1}{9.10}+...+\dfrac{1}{20.21}\right)\)

\(2.\left(\dfrac{1}{6}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{8}+\dfrac{1}{8}-\dfrac{1}{9}+\dfrac{1}{9}-\dfrac{1}{10}+...\dfrac{1}{20}+\dfrac{1}{21}\right)\)

\(=2.\left(\dfrac{1}{6}-\dfrac{1}{21}\right)=\dfrac{5}{21}\)

A = \(\dfrac{1}{21}+\dfrac{1}{28}+\dfrac{1}{36}+\dfrac{1}{45}+...+\dfrac{1}{210}\)

A = \(\dfrac{2}{42}+\dfrac{2}{56}+\dfrac{2}{72}+\dfrac{2}{90}+...+\dfrac{2}{210}\)

A = \(\dfrac{2}{6.7}+\dfrac{2}{7.8}+\dfrac{2}{8.9}+\dfrac{2}{9.10}+...+\dfrac{2}{14.15}\)

A = \(2.\left(\dfrac{1}{6.7}+\dfrac{1}{7.8}+\dfrac{1}{8.9}+\dfrac{1}{9.10}+...+\dfrac{1}{14.15}\right)\)

A = \(2.\left(\dfrac{1}{6}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{8}+\dfrac{1}{8}-\dfrac{1}{9}+\dfrac{1}{9}-\dfrac{1}{10}+...+\dfrac{1}{14}-\dfrac{1}{15}\right)\)

A = \(2.\left(\dfrac{1}{6}-\dfrac{1}{15}\right)\)

A = \(2.\dfrac{1}{10}\)

A = \(\dfrac{2}{10}\)

A = \(\dfrac{1}{5}\)

sorry, mik làm lộn

Làm lại nha:
A = \(\dfrac{1}{21}+\dfrac{1}{28}+\dfrac{1}{36}+\dfrac{1}{45}+...+\dfrac{1}{210}\)

A = \(\dfrac{2}{42}+\dfrac{2}{56}+\dfrac{2}{72}+\dfrac{2}{90}+...+\dfrac{2}{420}\)

A = \(2.\left(\dfrac{1}{42}+\dfrac{1}{56}+\dfrac{1}{72}+\dfrac{1}{90}+...+\dfrac{1}{420}\right)\)

A = \(2.\left(\dfrac{1}{6.7}+\dfrac{1}{7.8}+\dfrac{1}{8.9}+\dfrac{1}{9.10}+...+\dfrac{1}{20.21}\right)\)

A = \(2.\left(\dfrac{1}{6}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{8}+\dfrac{1}{8}-\dfrac{1}{9}+\dfrac{1}{9}-\dfrac{1}{10}+...+\dfrac{1}{20}-\dfrac{1}{21}\right)\)

A = \(2.\left(\dfrac{1}{6}-\dfrac{1}{21}\right)\)

A = \(2.\dfrac{5}{42}\)

A = \(\dfrac{5}{21}\)

\(25\frac{2}{13}-\left(\frac{15}{17}+15\frac{2}{3}\right)=\frac{327}{13}-\left(\frac{15}{17}+\frac{47}{3}\right)\)

\(=\frac{327}{13}-\frac{844}{51}\)

\(=\frac{5705}{663}\)

\(\frac{5}{30}+\frac{15}{90}+\frac{250}{150}+\frac{350}{210}+\frac{45}{270}=\frac{1}{6}+\frac{1}{6}+\frac{5}{3}+\frac{5}{3}+\frac{1}{6}\)

\(=\frac{3}{6}+\frac{10}{3}\)

\(=\frac{1}{2}+\frac{10}{3}\)

\(=\frac{23}{6}\)

\(3\frac{1}{11}.\frac{27}{46}.1\frac{6}{17}.2\frac{4}{9}=\frac{34}{11}.\frac{27}{46}.\frac{23}{17}.\frac{22}{9}\)

\(=\frac{68}{9}.\frac{27}{34}\)

\(=6\)

A. 3,242 + 2,326 + 192 = 5,760

B. 520,401 + 27,429 - 13,965 = 534,865

C. 13,228 - (28,073 - 16,785) = 2,940

D. 86,572 - (58,406 + 9,275) = 18,891

a: \(3242+2326+192\)

\(=3242+192+2326\)

\(=3434+2326=5760\)

b: \(520401+27429-13965\)

\(=\left(520401+27429\right)-13965\)

\(=547830-13965=533865\)

c: \(13228-\left(28073-16785\right)\)

\(=13228+16785-28073\)

\(=\left(13228+16785\right)-28073\)

\(=30013-28073=1940\)

d: \(86572-\left(58406+9275\right)\)

\(=86572-67681\)

=18891

- Cách 1: Tính số bị chia, tính số chia rồi tính thương

a) 210 = 1024 ; 28 = 256

=> 210:28 = 1024:256 = 4

b) 46 = 4096 ; 43 = 64

=> 46:43 = 4096:64 = 64

c) 85 = 32768 ; 84 = 4096

=> 85:84 = 32768:4096 = 8

d) 74 = 2401

=> 74:74 = 2401:2401 = 1

- Cách 2: Chia hai lũy thừa cùng cơ số rồi tính kết quả.

a) 210:28 = 210-8 = 22 = 4

b) 46:43 = 46-3 = 43 = 64

c) 85:84 = 85-4 = 81 = 8

d) 74:74 = 74-4 = 70 = 1

a) Cách 1: 1024 : 256 = 4. Cách 2: 2¹⁰ : 2⁸ = 2^{10 – 8} = 2² = 4;

b) Cách 1: 4096 : 64 = 64. Cách 2: 4⁶ : 4³ = 4^{6 – 3} = 4³ = 64;

c) Cách 1: 32768 : 4096 = 8. Cách 2: 8⁵ : 8⁴ = 8^{5 – 4} = 8¹ = 8;

d) Cách 1: 2401 : 2401 = 1. Cách 2: 7⁴ : 7⁴ = 7^{4 – 4} = 7⁰ = 1.   

a) \(37\times46+37\times51+111\)

\(=37\times46+37\times51+37\times3\)

\(=37\times\left(46+51+3\right)\)

\(=37\times100\)

\(=3700\)

b) \(35\times215-35\times210-175\)

\(=35\times215-35\times210-35\times5\)

\(=35\times\left(215-210-5\right)\)

\(=35\times0\)

\(=0\)

c) \(172\times47+86\times8-34\times4\)

\(=4\times\left(43\times47+86\times2-34\right)\)

\(=4\times\left(2021+172-34\right)\)

\(=4\times2159\)

\(=8636\)

d) \(48\times56+28\times104\)

\(=48\times56+56\times52\)

\(=56\times\left(48+52\right)\)

\(=56\times100\)

\(=5600\)

 \(=210+46+\left(-210\right)+\left(-26\right)\)

\(=[210+\left(-210\right)]+[46+\left(-26\right)]\)

\(=0+20\) 

 =20

\(37\times46+37\times51+111\)

\(=37\times46+37\times51+37\times3\)

\(=37\times\left(46+51+3\right)\)

\(=37\times100\)

\(=3700\)

------------

\(172\times47+86\times8-34\times4\)

\(=172\times47+172\times4-34\times4\)

\(=172\times\left(47+4\right)-34\times4\)

\(=172\times51-34\times4\)

\(=172\times3\times17-17\times2\times4\)

\(=17\times\left(172\times3-2\times4\right)\)

\(=17\times\left(516-8\right)\)

\(=17\times508\)

\(=8636\)

------------

\(35\times215-35\times200-175\)

\(=35\times215-35\times200-35\times5\)

\(=35\times\left(215-200-5\right)\)

\(=35\times10\)

\(=350\)

------------

\(48\times56+28\times104\)

\(=48\times2\times28+28\times104\)

\(=28\times\left(48\times2+104\right)\)

\(=28\times200\)

\(=5600\)

88 800

261 304

không phải nhé

= 210 + 46 -210 -26

= (210 - 210 ) + ( 46 - 26 )

= 0 + 20

= 20 

Chúc bạn học giỏi ! Kết bạn với mình nha

\(=210+46-210-26\)

\(=\left(210-210\right)+\left(46-26\right)\)

\(=0+20\)

\(=20\)