Question

0+3+6+9+12+15+...+1002+1005

trả lời đúng thì cho 3 tick

Answer 1

(1005-0):2+1=503(số)

503x1005:2=252757

Answer 2

0 + 3 + 6 + 9 + ... + 1005

= 3.0 + 3.1 + 3.2 + 3.3 + ... + 1005

= 3(0 + 1 + 2 + 3 + ... + 1005)

= 3( 1005(1005+1) : 2 )

= 3( 1005.1006 : 2 )

= 3( 1005.503 )

= 3 . 505 515

= 1 516 545