Question

[Phạm Hoài Nam]

A=1.2+2.3+3.4+...............+98.99+99.100

B=1.3+2.4+3.5+...............+99.101

C=1.4+2.5+ 3.6+..............+99.102

D=4+12+24+40+..............+1904+19800

E=1+3+6+10+.................+4851+4950

F=6+16+30+48+..............+19600+19998

G=2+5+9+14+.................+4949+5049

H=1.2.3+2.3.4+...............+98.99.100

I=1²+2²+3²+...................+99²+100²

K=2²+4²+6²+......................+98²+100²

L=1²+3²+5²+.......................+97²+99²

M=1²-2²+3²-4²+....................+99²-100²

N=1.2²+2.3²+3.4²+...............+98.99²

P=1.3+3.5+5.7+................+97.99+99.101

Q=2.4+4.6+6.8+................+98.100+100.102

R=1³+2³+3³+4³+.....................+99³+100³

Answer 1

[GPSgaming]

nhiều quá vậy ?

Answer 2

[ngũ việt an]

Gọi A là biểu thức ta có: 
CÂU1 :A = 1.2+2.3+3.4+......+99.100 
          3A = 1.2.3 + 2.3.3 + 3.4.3 + … + 99.100.3 
          3A = 1.2.3 + 2.3.(4 - 1) + 3.4.( 5 - 2) + … + 99.100. (101 - 98) 
          3A = 1.2.3 + 2.3.4 - 1.2.3 + 3.4.5 - 2.3.4 + … + 99.100.101 - 98.99.100 
          3A = 99.100.101 
          A = 99.100.101 : 3 
          A = 33.100.101 
          A = 333 300