Eli
With the help of this equation editor,
it is easy to typeset in LaTeX:
\begin{bmatrix}
1 & 2 & 3 & 4 & 5 & 6& 7 & 8& 9& 10\\
11& 12 & 13 & 14 & 15 & 16 & 17 & 18 & 19 & 20\\
21& 22 & 23 & 24 & 25 &26 &27 &28 & 29 & 30\\
31& 32& 33& 34 & 35& 36& 37 & 38& 39& 40\\
41& 42 & 43 & 44 & 45& 46& 47& 48& 49&50 \\
51& 52 & 53 & 54 & 55& 56 & 57 & 58 & 59 & 60\\
61& 62 & 63 & 64 & 65& 66 & 67 & 68 & 69 & 70\\
71& 72 & 73 & 74 & 75 & 76& 77 & 78& 79 &80 \\
81& 82& 83& 84 & 85 & 86 & 87& 88 & 89 & 90\\
91& 92 & 93 & 94 & 95 & 96 & 97 &98 & 99 & 100
\end{bmatrix}