You can download VisiCalc from Dan Bricklin's site at http://www.bricklin.com/history/vcexecutable.htm and run it using dosbox. Tip: a formula is something like "+A1" instead of "=A1".
You can see some behavior differences compared to modern spreadsheets, notably: there's no operator precedence in VisiCalc. 1 + 2 * 3 = 9 (instead of 7), because this imitated the behavior of simple calculators. Bricklin realized VisiCalc was competing against people with paper and calculators, and anything that made it harder or slower than that would hurt adoption.