517,5 tk nhé

345+345:2

=345+172,5

=517,5

ok 100% đúng

345 + 345 : 2

= 345 + 172,5

= 517,5

nhân chia trước cộng trừ sau nha

\(1000-345+345:y=655+345:y\)

\(y:2\times5+1234=2234\)

\(\Rightarrow y:2\times5=1000\)

\(\Rightarrow y:2=200\)

\(\Rightarrow y=400\)

\(\left(\frac{3}{17}-\frac{2}{345}+\frac{5}{12}\right)-\left(-\frac{2}{345}+\frac{3}{17}-\frac{1}{12}\right)\)

\(=\frac{3}{17}-\frac{2}{345}+\frac{5}{12}+\frac{2}{345}-\frac{3}{17}+\frac{1}{12}\)

\(=\left(\frac{3}{17}-\frac{3}{17}\right)+\left(\frac{2}{345}-\frac{2}{345}\right)+\frac{5}{12}+\frac{1}{12}\)

\(=\frac{6}{12}=\frac{1}{2}\)

( 3/17 - 2/345 + 5/12 ) - ( - 2/345 + 3/17 - 1/12 )

= 3/17 - 2/345 + 5/12 + 2/345 - 3/17 + 1/12

= ( 3/17 - 3/17 ) + ( 2/345 - 2/345 ) + ( 5/12 + 1/12 )

= 0 + 0 + 1/2

=1/2

ế khum hiểu sao vẫn ế

Ta có:

345:5+345=414

Vì dãy số có 100 số hạng nên:

414+414+414+......+414=414x100=41400

Đáp số:............

\(1000 − 345 + 345 : y = 655 + 345 : 5\)

\(655 + 345 : y = 655 + 69\)

\(345 : y = 655 + 69 − 655\)

\(345 : y = ( 655 − 655 ) + 69\)

\(345 : y = 0 + 69\)

\(y = 345 : 69\)

\(y = 5\)

`#Ya`

345.123-345.20-345.3

=345.[123-20-3]

=345.100

=34500

Bài 2. Tính nhanh
a) 27 + (-2019) + (-27)

= 27 -2019 -27

=(27 - 27) -2019

=0-2019

= -2019

d) (-102) – (345 – 102)

= -102 - 345 +102

= (102 - 102) -345

= 0-345

= -345

b) (-10) + 23 + (-20) + 30

= -10 +23-20+30

= -(10+20) +23 +30

= -30 +23 +30

= (30-30) +23

= 0 +23

= 23

e) (12 + 34 – 56) – (12 – 56)

= 12 +34 -56 -12 +56

= (12-12) + (56-56) +34

= 0+0 +34

= 34

c) (-2).125.(-5).(-8).(+17)

=[(-2) . (-5)] . [ 125.(-8)] . (+17)

= 10 . (-1000).(+17)

= - 10000 . 17

= - 170000

f) 37.(-345) – 345.(-47)

= -345 . (37-47)

= -345.(-10)

=3450

123 - 5 x 9

= 123 - 45

= 78

1257 x 2 - 345

= 2514 - 345

= 2169

99 x 9 + 357

=891 + 357

= 1248

4793 x 3 + 8

= 14379 + 8

=  14387

594 - 3 x 7

=594 - 21

= 537

555 - 177 x 2

= 555 - 354

= 201

345 : 3 + 9

= 115 + 9

=124

(345 + 555) x 3

= 900 x 3

= 2700

k cho mk nha Trần Đại Thành Danh

123-5*9=123-45=78

1257*2-345=2514-345=2169

99*9+357=891+357=1248

4793*3+8=14379+8=14387

594-3*7=594-21=573

555-177*2=555-254=201

345:3+9=115+9=124

(345+555)*3=900*3=2700

123 - 5 x 9=

=123- 45

=78

1257 x 2 - 345=

= 2514-345

=2169

99 x 9 + 357=

=891 + 357

=1248

4793 x 3 + 8=

= 14319 + 8

= 14387

594 - 3 x 7=

= 594 - 21

=537

555 - 177 x2=

= 555- 354

=201

345 : 3 + 9=

=115 + 9

=124

(345 + 555) x 3=

= 900 x 3

= 2700

nhớ k nhé