“This,” he would say, showing an integral with live units, “is what mathematical thinking felt like before everything became code.” In 2025, Mathcad still exists, but the “Studentenversion” as a physical CD-ROM is a memory. Yet its spirit lives on in modern tools like Jupyter notebooks (code and text together) and Notion with LaTeX (live equations). But none of them, Klaus argues, have the tactile simplicity of clicking inside an equation and seeing the result appear right below it, exactly as written.
In the autumn of 1999, Klaus Brenner was a third-semester engineering student at the TU Berlin. He had a problem. His Höhere Mathematik professor expected clean, logical homework, but Klaus’s pages were a mess of scratched-out integrals, arrows moving terms from one line to the next, and coffee stains.
Symbolically, it was messy. Klaus typed the equations into Mathcad, used a solve block (the legendary Given ... Find ), and Mathcad returned: x = 3, y = 4 and x = 4, y = 3 . He checked: 3*4=12, 9+16=25. Perfect.