Observe the following pattern `1^2=1/6[1xx(1+1)xx(2xx1+1)]`, `1^2+2^2=1/6[2xx(2+1)xx(2xx2+1)]`, `1^2+2^2+3^2=1/6[3xx(3+1)xx(2xx3+1)],` `1^2+2^2+3^2+4^2=1/6[4xx(4+1)xx(2xx4+1)],` and find the values of each of the following `1^2+2^2+3^2+4^2+ddot+10^2,` `5^2+6^2+7^2+8^2+9^2+10^2+11^2+12^2`