What is the value of 17^2 + 18^2 + 19^2 + 20^2 + 21^2 + 22^2 + 23^2 ?  Pick:	A) 2898	B) 2808	C) 2818	D) 2828	E) 2838
This is what I did, all the nos are close to 20, and squared, so 20^2 plus there are 7 numbers, so (20)^2 x 7 =2800,   now squaring the last digits of each no individually comes up to   (9+4+1+0+1+4+9)= 
<gadget id="calculator">  (9+4+1+0+1+4+9)</gadget>
<output>28</output>
28.   when you add the 2 up it gives you a  (2800+28)= 
<gadget id="calculator"> (2800+28)</gadget>
<output>2_828</output>
2828,   Answer is 2828 IMO.
<result>D</result>
What is the value of 17^2 + 18^2 + 19^2 + 20^2 + 21^2 + 22^2 + 23^2 ?