# Giải toán trên mạng

o l m . v n

Được cập nhật 29 tháng 9 lúc 20:44

Báo cáo sai phạm

Số số hạng là :

$$\left(x+10\right)+1=x-9$$số hạng

Tổng là :

$$\left(x+10\right).\left(x-9\right)=10212$$

$$\Rightarrow\left(x+10\right)\left(x-9\right)=\left(101+10\right)\left(101-9\right)$$

$$\Rightarrow x=101$$

Báo cáo sai phạm

Cách 1

10+11+12+13+...+X = 5106

1+2+3+4+5+6+7+8+9+10+11+12+13+...+X=5151

=> [X.(X+1)]:2=5151

X.(X+1)=10302

X.(X+1)=101.102

=>X=101

Cách 2

Từ 10 đến 19 có
19 – 10 + 1 = 10 số
Từ 20 đến 29 có
29 – 20 + 1 = 10 số
….
Chữ số hàng chục là 1 hoăc 2,3,4… thì hàng chục lần lượt là
10 x 10 = 100
20 x 10 = 200
30 x 10 = 300
….
Và mỗi hàng chục như vậy lại có hàng đơn vị có tổng đều bằng
0 + 1 + 2 + … + 9 = 45
Vậy từ 10 đến 99 có tổng bằng
100 + 200 + 300 + … + 900 + 45 x 9 ( hàng đơn vị lặp lại từ 1 đến 9 là 9 lần nên nhân 45 với 9)
= 4500 + 45 x 9 = 4905
Lại có 4905 + 100 + 101 = 5106.
Đáp số X = 101

Báo cáo sai phạm

Số số hạng dãy trên có là:

( x - 10 ) + 1 = x - 9 ( số hạng )

Tổng trên là:

( x + 10 ) . ( x - 9 ) = 10212

=> ( x + 10 ) . ( x - 9 ) = 111 . 92

=> ( x + 10 ) . ( x - 9 ) = ( 101 + 10 ) . ( 101 - 9 )

=> x = 101

Báo cáo sai phạm

x=101

Báo cáo sai phạm

101 chắc chắn 10000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 00 00000 00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 00 00000 00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 00 00000 00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 00 00000 00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 00 00000 00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 00 00000 00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000

Báo cáo sai phạm

X=101

Báo cáo sai phạm

đây là dạng toán lớp 5

Báo cáo sai phạm

101 chăc chắn

10000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000%

Báo cáo sai phạm

101 chắc chắn 1000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000%

Báo cáo sai phạm

Trần Hải An & huynh anh thuchỉ cho mk qui tắc tính tổng đc ko cả Tsurugi Kyousuke

Báo cáo sai phạm

Tổng các số tự nhiên từ 1 đến X là : ( X+ 1 ) x X : 2 = 5106 Mà tổng các số tự nhiên từ 1 đến 9 là 45.Vậy ( X + 1 ) x X : 2 – 45 = 5106 ; ( X + 1 ) x X : 2 = 5106 + 45 ; ( X + 1 ) x X : 2 = 5151 ; ( X + 1 ) x X = 5151 x 2 ; ( X + 1 ) x X = 10302 ; ( X + 1 ) x X = 101 x ( 101+1) Vậy suy ra X = 101.

Báo cáo sai phạm

Từ 10 đến 19 có
19 – 10 + 1 = 10 số
Từ 20 đến 29 có
29 – 20 + 1 = 10 số
….
Chữ số hàng chục là 1 hoăc 2,3,4… thì hàng chục lần lượt là
10 x 10 = 100
20 x 10 = 200
30 x 10 = 300
….
Và mỗi hàng chục như vậy lại có hàng đơn vị có tổng đều bằng
0 + 1 + 2 + … + 9 = 45
Vậy từ 10 đến 99 có tổng bằng
100 + 200 + 300 + … + 900 + 45 x 9 ( hàng đơn vị lặp lại từ 1 đến 9 là 9 lần nên nhân 45 với 9)
= 4500 + 45 x 9 = 4905
Lại có 4905 + 100 + 101 = 5106.
Đáp số x = 101

Báo cáo sai phạm

Từ 10 đến 19 có
19 – 10 + 1 = 10 số
Từ 20 đến 29 có
29 – 20 + 1 = 10 số
….
Chữ số hàng chục là 1 hoăc 2,3,4… thì hàng chục lần lượt là
10 x 10 = 100
20 x 10 = 200
30 x 10 = 300
….
Và mỗi hàng chục như vậy lại có hàng đơn vị có tổng đều bằng
0 + 1 + 2 + … + 9 = 45
Vậy từ 10 đến 99 có tổng bằng
100 + 200 + 300 + … + 900 + 45 x 9 ( hàng đơn vị lặp lại từ 1 đến 9 là 9 lần nên nhân 45 với 9)
= 4500 + 45 x 9 = 4905
Lại có 4905 + 100 + 101 = 5106.
Đáp số x = 101

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