a) 35.34 + 35.86 + 65.75 + 65.45 =

( 35 + 65 ) x ( 34 + 86 ) + ( 75 + 45 )

100 x 120 x 120

100 x 14400

1440000

\(35\cdot34+35\cdot86+65\cdot75+65\cdot45\\ =35\cdot\left(34+86\right)+65\cdot\left(75+45\right)\\ =35\cdot120+65\cdot120\\ =120\cdot\left(35+65\right)\\ =120\cdot100\\ =12000\)

Xét\(3A=1\cdot2\left(3-0\right)+2\cdot3\left(4-1\right)+\cdot\cdot\cdot+99\cdot100\left(101-98\right)\)

     \(3A=1\cdot2\cdot3-0\cdot1\cdot2+2\cdot3\cdot4-1\cdot2\cdot3+...+99\cdot100\cdot101-98\cdot99\cdot100\)

     \(3A=99\cdot100\cdot101\)

\(\Rightarrow A=33\cdot100\cdot101=30300\)

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

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

3A = 1 . 2 . ( 3 - 0 ) + 2 . 3 . ( 4 - 1 ) + 3 . 4 . ( 5 - 2 ) + ... + 99 . 100 . ( 101 - 98 )

3A = 1. 2 . 3 - 0 . 1 . 2 6 2 . 3 . 4 - 1 . 2 . 3 + 3 . 4 . 5 + 2 . 3 . 4 + ... + 99 . 100 . 101 - 98 . 99 . 100

3A = ( 1 . 2 . 3 - 1 . 2 . 3 ) + ( 2 . 3 . 4 - 2 . 3 . 4 ) + ... + ( 98 . 99 . 100 - 98 . 99 . 100 ) + ( 99 . 100 . 101 - 0.1 . 2 )

3A = 0 + 0 + 0 + ... + 0 + 99 . 100 . 101 - 0 . 1 . 2

3A = 99 . 100 . 101 - 0

A = \(\frac{99\cdot100\cdot101}{3}=333300\)

\(35\cdot34+35\cdot86+65\cdot75+65\cdot45=35\left(34+86\right)+65\left(75+45\right)\)

                                                                              \(=35\cdot120+65\cdot120\)

                                                                                \(=120\left(35+65\right)\)

                                                                                \(=120\cdot100=12000\)

bạn ơi coi lại để thử đi

đúng đề rồi bn ơi

a) 37.75+37.45+63.67+63.53

= 37.(75+45)+63.(67+53)

= 37.120+63.120

= 120.(37+63)

= 120.100

= 12000

b) 35.34+35.86+65.75+65.45

= 35.(34+86)+65.(75+45)

= 35.120+65.120

=120.(35+65)

= 120.100

= 12000

c) 78.31+78.24+78.17+22.72

= 78.(31+24+17)+22.72

= 78.72+22.72

= 72.(78+22)

= 72.100

= 7200

$\mathrm{a)\; 37}.75+37.45+63.67+63.53$

$=37.(75+45)+63.(67+53)$

$=37.120+63.120$

$=(37+63).120$

$=100.120$

$=12000$

b) 35⋅34+35⋅86+65⋅75+65⋅45=35(34+86)+65(75+45)=35⋅120+65⋅120=(35+65)⋅120=

$\mathrm{a)\; 37}.75+37.45+63.67+63.53$

$=37.(75+45)+63.(67+53)$

$=37.120+63.120$

$=(37+63).120$

$=100.120$

$=12000$

b) 35 . 34 + 35 . 86 + 65 . 75 + 65 . 45

= 35 . ( 34 + 86 ) + 65 . ( 75 + 45 )

= 35 . 120 + 65 . 120

= ( 35 + 65 ) . 120

= 100 . 120

=12000

c) 78 . 31 + 78 . 24 + 78 . 17 + 22 . 72

= 78 . ( 31 + 24 + 17 ) + 22 . 72

= 78 . 72 + 22 . 72

= 72 . ( 78 + 22 )

= 72 . 100

= 7200

chúc bạn học tốt

A,35*34+35*86+65*75+65*45

=35*[34+86]+65*[75+45]

=35*100+65*120

=35*100+65*100+65*20

=[35+65]*100+65*20

=10000+1300=11300

a) 35× 34 +35× 86 + 65 × 75 + 65× 45

= 35× ( 34+86) + 65× (75 + 45)

= 35× 120 + 65 × 120

= 120 × ( 35 + 65)

= 120 × 100 = 12000

a, 35.34 + 35.86 + 65.75 + 65.75 

= 35.(34 + 86) + 75.(65 + 65) 

= 35.120 + 75.130 

= 4200 + 9750

= 13950

b, 3.25.8 + 4.37.6 + 2.38.12 

= 24.25 + 24.37 + 24.38 

= 24.(25 + 37 + 38)

= 24. 100

= 2400 

c,66.25 + 5.66 + 66.14 + 33.66

= 66 . (25 + 5 + 14 + 33) 

= 66 .77

=5082

d, 48 .19 + 48.115 + 134.52 

= 48 . (19 + 115) + 134.52 

= 48 . 134 + 134.52 

= 134 . (48 + 52) 

= 134 . 100 

= 13400

35.34+35.85+75+65.75

=13950

3.25.8+4.37.6=2.38.12

=2400

66.25+5.66+66.14+33.66

=5082

48.19=48.115+134.52

=13400

hok tốt

35.34+35.85+75+65.75

=13950

3.25.8+4.37.6=2.38.12

=2400

66.25+5.66+66.14+33.66

=5082

48.19=48.115+134.52

=13400

hok tốt

a)

\(\Rightarrow35.\left(34+86\right)+65.\left(75+45\right)\)

\(\Rightarrow35.120+65.120\)

\(\Rightarrow120.\left(35+65\right)=120.100=12000\)

b)

\(\Leftrightarrow21.49-11.49+90.49+49.125.16\)

\(\Rightarrow49.\left(21-11+90+2000\right)\)

\(\Rightarrow49.2100=102900\)

a) 35 . 34 + 35 . 86 + 65 . 75 + 65 . 45
= 35 . ( 34 + 86 ) + 65 . ( 75 + 45 )
= 35 . 120 + 65 . 120
= ( 35 + 65 ) . 120
= 100 . 120
= 12000

b) 21 . 7² - 11 . 7² + 90 . 7² + 49 . 125 . 16
= 21 . 49 - 11 . 49 + 90 . 49 + 49 . 125 . 16
= ( 21 - 11 + 90 ) . 49 + 49 . 125 . 8 . 2
= 100 . 49 + 49 . 2 . 1000
= 100 . 49 + 49 . 2000
= ( 100 + 2000 ) . 49
= 2100 . 49
= 102900

a, 35.34 + 35.86 + 65.75 + 65.45

= 35.(34 + 86) + 65.(75 + 45)

= 35.120 + 65.120

= 120.(35+65)

= 120.100

= 12000

b, \(7.5^2-32:2^3+9\)

= 7.25 - 32:8 + 9

= 175 - 4 + 9

= 180