Question

1+(-2)+3+(-4)+5+.......+99+(-100)+101

Answer 1

= { 1 + ( - 2 ) } + { 3 + ( - 4 ) } + { 5 +( - 6 ) } + ....... + { 99 + ( - 100 ) } + 101

= ( - 1 )           + ( - 1 )           +   ( - 1 )       + ........ +   ( - 1 )              + 101

Ta có : ( 100 - 1 ) : 1 + 1 = 100 ( số hạng )

Vậy có 100 : 2 = 50 ( cặp )

= ( - 1 ) . 50 + 101

= ( - 50 ) + 101

= 51 

Tích mk nha Nguyễn Thị Thúy Vy

Answer 2

Bạn ghép cặp nha

[1+(-2)]......+[99+(-100)]+101

=-1+....-1+101

=-1x50+101=-50+101=-51

Answer 3

    \(1+\left(-2\right)+3+\left(-4\right)+5+...+99+\left(-100\right)+101\)\(=1-2+3-4+5+...+99-100+101\)

\(=\left(1+3+5+...+101\right)-\left(2+4+6+...+100\right)\)

Từ 1 đến 101,ta có:

 \(\left(101-1\right):2+1=51\)

\(1+...+101=\left(1+101\right).51:2=2601\)

Từ 2 đến 100,ta có:

\(\left(100-2\right):2+1=50\)

\(2+...+100=\left(100+2\right).50:2=2550\)

\(\Rightarrow\)\(2601-2550=51\)

Answer 4

\(1+\left(-2\right)+3+\left(-4\right)+....+99+\left(-100\right)+101\)\(101\)
\(=\left[1+\left(-2\right)\right]+\left[3+\left(-4\right)\right]+....+\)\(\left[99+\left(-100\right)\right]+101\)
\(=\left(-1\right)+\left(-1\right)+.......+\left(-1\right)+101\)
\(=\left(-1\right).50+101\)
\(=\left(-50\right)+101\)
\(=51\)