Get elements of lists

v = Range[10] ^ 2

{1, 4, 9, 16, 25, 36, 49, 64, 81, 100}

Part[v, 3]

9

v[[3]]

9

v[[1 ;; 5]]

{1, 4, 9, 16, 25}

v[[5 ;; 8]]

{25, 36, 49, 64}

v[[-7 ;; ]]

{16, 25, 36, 49, 64, 81, 100}

m = Partition[Range[25] ^ 2, 5]

{{1, 4, 9, 16, 25}, {36, 49, 64, 81, 100}, {121, 144, 169, 196, 225}, {256, 289, 324, 361, 400}, {441, 484, 529, 576, 625}}

MatrixForm[m]

MatrixForm[{{1, 4, 9, 16, 25}, {36, 49, 64, 81, 100}, {121, 144, 169, 196, 225}, {256, 289, 324, 361, 400}, {441, 484, 529, 576, 625}}]

m[[1]]

{1, 4, 9, 16, 25}