Question

Biết rằng : 1²  + 2² + 3² + 10² = 385

Tính : S = 100² + 200² + 300² + ... + 1000²

Answer 1

S=100²+200²+300²+.......+1000²

S=100².(1²+2²+3²+.........+10²)

S=10000 .385

S=3850000

Answer 2

S= 100²+200²+300²+...+1000²

S= 1² .100²+2².100²+3².100²+...+10².1000²

S= 100².( 1²+2²+3²+...+10²)

S= 10 000 .385

=>S= 3850000

Answer 3

S = 100^2.385 = 10000.385 = 3850000

Answer 4

Ta có : 100² + 200² + 300² + ...... + 1000²

= 1².100² + 2².100² + 3².100² + ....... + 10².100²

= 100²(1² + 2² + 3² + ....... + 10²)

= 10000 x 385

= 385 00000

Answer 5

Ta có: S=100²+200²+...+1000²

             =100²x(1²+2²+...+10²)

             =10000x385=3850000

Vậy S=3850000