Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
(1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20 ) -1-5-9-3=
= ( 1 + 20 ) x 20 : 2 - 1 - 5 - 9 - 3
= 210 - 1 - 5 - 9 - 3
= 192
hok tốt
bn rảnh ghê ha
1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20-1-5-9-3=192
1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20+21=231
trả lời:
=231
Laughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cowLaughing cow
= 1+(2-3)+(4-5)+(6-7)+........+(18-19)+20
= 1+(-1)+(-1)+(-1)+........+(-1)+20
= 1+(-9)+20
= 12
(1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20)*(21*4+6-84)=330
X = ( 1+10 ) * 10 / 2 = 11 * 10 / 2 = 110 / 2 = 55
X= (2+20) * 10 /2 = 110
X= (1+19)*10/2= 100
1+2+3+4+5+6+7+8+9+10= (10+1)X10 : 2 = 55
2+4+6+8+10+12+14+16+18+20 = (20+2)x10 : 2 = 110
1+3+5+7+9+11+13+15+17+19 = (19+1) x 10 : 2 = 100
Áp dụng công thức tính dãy số cách đều ta có:
1 + 2 + 3 + ... + 20
= (1 + 20) x 20 : 2
= 21 x 10
= 210
Cách 1:
Áp dụng công thức tính dãy số ta có
[(20 - 1) : 1 + 1] x (20 + 1) : 2
= 20 x 21 : 2
= 10 x 21
= 210
Cách 2 :
1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12 + 13 + 14 + 15 + 16 + 17 + 18 + 19 + 20
= (20 +1 ) + (19 + 2) +....+ (11+ 10)
= 21 + 21 + ....+ 21 ( 10 số 21)
= 21 x 10
= 210
210
Em ơi ? đáp án là 210 đó nha .
=210
= 199
210
1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12 + 13 + 14 + 15 + 16 + 17 + 18 + 19 + 20
= 20 x (20 + 1) : 2 = 210
210
𝓗𝓪𝓗𝓪▄︻̷̿┻̿═━一♛▄︻̷̿┻̿═━一♛▄︻̷̿┻̿═━一♛▄︻̷̿┻̿═━一♛𝓪𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一▄︻̷̿┻̿═━一𝓗𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗𝓗𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一𝓗𝓗▄︻̷̿┻̿═━一𝓗▄︻̷̿┻̿═━一