đây mà là toán lớp 1 à.đồ dở hơi.

ban a toán lớp mấy thì  toán vậy bạn có trả lời được ko mà còn ra vẻ hả bạn 'doraemi'

dúng rồi đó ko trả lời thì thôi 

k

Trl

Mà

kb

Đc k?

= 351 nha

1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12 + 13 + 14 + 15 + 16 + 17 + 18 + 19 + 23 + 24 + 25 + 26 + 27 + 28 + 29 = 372

\(\frac{4}{6}+\frac{7}{13}+\frac{17}{9}+\frac{19}{13}+\frac{1}{9}+\frac{14}{6}\)

\(=\left(\frac{4}{6}+\frac{14}{6}\right)+\left(\frac{7}{13}+\frac{19}{13}\right)+\left(\frac{17}{9}+\frac{1}{9}\right)\)

\(=3+2+2=7\)

 4/6 + 7/13 + 17/9 + 19/13 + 1/9 + 14/6. = ( 4/6 + 14/6 ) + ( 7/13 + 19/13 ) + ( 17/9 + 1/9 ). = 18/6 + 26/13 + 18/9. = 3 + 2 + 2 = 7.

\(\frac{4}{6}+\frac{7}{13}+\frac{17}{9}+\frac{19}{13}+\frac{1}{9}+\frac{14}{6}=\left(\frac{4}{6}+\frac{14}{6}\right)+\left(\frac{7}{13}+\frac{19}{13}\right)\)\(+\left(\frac{17}{9}+\frac{1}{9}\right)=\frac{18}{6}+\frac{26}{13}+\frac{18}{9}=3+2+2=7\)

cậu ấn máy tính không được à

Phải trình bày rõ ràng chứ

a) \(1-5+7-8+4-1+5-7+8\)

\(=\left(1-1\right)+\left(5-5\right)+\left(7-7\right)+\left(8-8\right)+4\)

\(=0+0+0+0+4\)

\(=4\)

b) \(12-14+9-3-14+9-3+14-19-9-12\)

\(=\left(12-12\right)+\left(9-9\right)+\left(14-14\right)+9-3-3\)

\(=0+0+0+9-6\)

\(=3\)

c) \(20-4+8-17+4-8-20+15\)

\(=\left(20-20\right)+\left(4-4\right)+\left(8-8\right)+\left(-17+4+15\right)\)

\(=0+0+0+2\)

\(=2\)

\(13-98+91-75+98-91-13\)

\(=\left(13-13\right)+\left(98-98\right)+\left(91-91\right)-75\)

\(=0+0+0-75\)

\(=-75\)

\(\frac{5}{6}+\frac{7}{13}+\frac{17}{9}+\frac{19}{13}+\frac{1}{9}+\frac{7}{6}\)

\(=\left(\frac{5}{6}+\frac{7}{6}\right)+\left(\frac{17}{9}+\frac{1}{9}\right)+\left(\frac{19}{13}+\frac{7}{13}\right)\)

\(=\frac{12}{6}+\frac{18}{9}+\frac{26}{13}\)

\(=2+2+2\)

\(=4+2\)

\(=6\)

\(\frac{5}{6}+\frac{7}{13}+\frac{17}{9}+\frac{19}{13}+\frac{1}{9}+\frac{7}{6}.\)

\(=\left(\frac{5}{6}+\frac{7}{6}\right)+\left(\frac{7}{13}+\frac{19}{13}\right)+\left(\frac{17}{9}+\frac{1}{9}\right)\)

\(=\frac{12}{6}+\frac{26}{13}+\frac{18}{9}\)

\(=2+2+2\)

\(=6\)

20 - 19 + 18 - 17 + 16 - 15 + 14 - 13 + 12 - 11 + 10 - 9 + 8 - 7 + 6 - 5 + 4 - 3 + 2 - 1

= ( 20 - 19 ) + ( 18 - 17 ) + ( 16 - 15 ) + ( 14 - 13 ) + ( 12 - 11 ) + ( 10 - 9 ) + ( 8 - 7 ) + ( 6 - 5 ) + ( 4 - 3 ) + ( 2 - 1 )

= 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1

= 1 . 10

= 10

20 - 19 + 18 - 17 + 16 - 15 + 14 - 13 + 12 - 11 + 10 - 9 + 8 - 7 + 6 - 5 + 4 - 3 + 2 - 1  

=  1      +    1      +     1      +    1      +     1    +    1      +  1    +   1    +   1    +  1

= 10

20 - 19 + 18 - 17 + 16 - 15 + 14 - 13 + 12 - 11 + 10 - 9 + 8 - 7 + 6 - 5 + 4 - 3  + 2 - 1 

=    1 +   1 + 1 + 1 + 1 + 1 + 1 + 1 +1+ 1

= 10

   1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20

= (1+19)+(2+18)+(3+17)+(4+16)+(5+15)+(6+14)+(7+13)+(8+12)+(9+11)+(10+20)

=   20   +   20   +   20   +   20  +   20    +   20  +   20   +    20   +   20  +30

=  20x9 +30

=180+30

=210

tk cho mik nhé

\(\frac{\left(20+1\right)x20}{2}\)

=(1+19)+(2+18)+(3+17)+(4+16)+(5+15)+(6+14)+(7+13)+(8+12)+(9+11)+10

=20+20+20+20+20+20+20+20+20+10

=190

wow! mù mắt. Ido tính toán có khác!

C2:(32+1)x32:2=528

bạn tính thử xem đúng đấy.

wowwowwow

1+2+3+4+5+6+7+8+9+10=55

11+12+13+14+15+16+17+18+19+20=155

1+2+3+4+5+6+7+8+9+10+11+12+13+14 +15+16+17+18+19+20+21+22+23+24+25+26+27+28+29+30-50-53=362

1+2+3+4+5+6+7+8+9+10=55

11+12+13+14+15+16+17+18+19+20=155

1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20+21+22+23+24+25+26+27+28+29+30-50-53=362