Question

(-30)+(-29)+....+48+49+50

Answer 1

Ai biết giúp mk

Answer 2

\(\left(-30\right)+\left(-29\right)+.......+48+49+50\)

=\(\left(\left(-30\right)+30\right)+\left(\left(-29\right)+29\right)+\left(\left(-1\right)+1\right)+31+32+....49+50\)

\(=31+32+..........+49+50\) = \(\left(31+49\right)\left(32+48\right)+..........\left(40+40\right)+50\)

\(\left(80.9\right)+50=720+50=770\)

Answer 3

\(\left(-30\right)+\left(-29\right)+.....+48+49+50\)

\(=\left[\left(-30\right)+30\right]+\left[\left(-29\right)+29\right]+.....+\left[1+\left(-1\right)\right]+31+32+.....+50\)\(=0+0+0+...+31+32+33+....+50\)

\(=\left(\dfrac{50-31}{1}+1\right):2\left(50+31\right)=810\)

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