b,5.7.77-7.60+49.25-15.42

=35.77-35.12+35.35-35.18

=35(77-12-35-18)

=35.12

=420

tick nha

Ngồi bấm máy tính mà làm sao chậm đc!! =)) Nguyen Huu The

a) 2.53.12+4.6.87-3.8.40

= (2.12).53+(4.6).87-(3.8).40

= 24.53+24.87-24.40

= 24.(87+53)-24.40

= 24. 140-24.40

= 24.(140-40)

= 24.100

= 2400

b) tịt

a: \(2\cdot53\cdot12+4\cdot6\cdot87-3\cdot8\cdot40\)

\(=24\left(53+87-40\right)\)

=2400

b: \(5\cdot7\cdot77+7\cdot60+49\cdot25-45\cdot42\)

\(=35\cdot77+35\cdot12+49\cdot25-45\cdot42\)

\(=35\cdot89+35\left(7\cdot5-9\cdot6\right)\)

\(=35\cdot70=2450\)

a) 2.53.12+4.6.87-3.8.40

=24.53+24.87-24.40

=24.(53+87-40)

=24.100

=2400

b) 5.7.77-7.60+49.25-45.42

=5.7.77-7.60+7.7.25-45.6.7

=7.(5.77-60+7.25-6.45)

=7.230

=1610

a,5.7.77-7.60+7.7.25-15.6.7

=7.385-7.60+175.7-90.7

=7.(385-60+175-90)

=7.410

=2870

nhầm còn câu b

a) $53.39+47.39-53.21-47.21$

$=39.(53+47)-21.(53+47)$

$=(39-21).100=18.100=1800$

b) $2.53.12+4.6.87-3.8.40$

$=24.53+24.87-24.40=24.(53+87-40)=24.100=2400$

c) $5.7.77-7.60+49.25-15.42$

$=7.385-7.60+7.175-90.7$

$=7.(385-60+175-90)=7.410=2870$

\(53.39+47.39-53.21-47.21\)

\(=39(47+53)-21(47+53)\)

\(=(39-21)(47+53)\)

\(=18.100=1800\)

\(2.53.12+4.6.87-3.8.40\)

\(=24.53+24.87-24.40\)

\(=24(53+87-40)=24.100=2400\)

\(5.7.77-7.60+49.25-15.42\)

\(=385.7-7.60+7.7.25-15.6.7\)

\(=385.7-7.60+7.175-7.90\)

\(=7(385-60+175-90)=7.410=2870\)

a, 53.39+47.39-53.21-47.21

=39.(53+47)-21.(53+47)

=39.100-21.100

=100.(39-21)

=100.18

=1800

b,b,2.53.12+4.6.87-3.8.40

=24.53+24.87-24.40

=24.(53+87-40)

=24.100

=2400

c,5.7.77-7.60+49.25-15.42

=7.385-7.60+7.175-90.7

=7.(385-60+175-90)

=7.410

=2870

Chúc bạn học tốt

53 x 39 + 47 x 39 + 53 x 21 + 47 x 21

= 39 x (53 + 47) + 21 x (53 + 47)

= 39 x 100 + 21 x 100

= 100 x (39 + 21)

= 100 x 40

= 4000

2 x 53 x 12 + 4 x 6 x 87 - 3 x 8 x 40

= 1272 + 2088 - 960

= 3360 - 960

= 2400

5 x 7 x 77 - 7 x 60 + 49 x 25 - 15 x 42

= 2695 - 420 + 1225 - 630

= 2275 + 595

= 2870

Học tốt!!!

a/ 53.39+47.39-53:21+47.21=488447619

b/2.53.12+4.6.87-3.8.40=6860208

c/5.7.77-7.60+49.25-15.42=2870

Tớ bó tay luôn

\(5.7.77-7.60+49.25-15.42\)

\(=\)\(5.7.7.11-7.5.12+7.7.5.5-5.3.7.6\)

\(=\) \(7.5.\left(77-12+35-18\right)\)

\(=\) \(35.82\)

\(=\) \(2870\)

5.7.77 - 7.60 + 49.25 - 15.42

=5.7.(77-12+7.5-3.6)

=35.82

=35.80+35.2

=2800+70

=2870

Ta có :

1 / 5.7.77=2695

2 / 7.60=420

3 / 49.25=1225

4 / 15.42=630

Vậy 5.7.77 - 7.60 + 49.25 - 15.42 = 2695-420+1225-630=2870

Vậy đáp số là 2870

tính thuận tiện đó à

5 . 7 . 77 - 7 . 60 + 49 . 25 - 15 . 42 = 2870

Tích ủng hộ mik thoát khỏi điểm âm nha