How many millimeters makes one square meter?

Answer 1

You can't convert between linear and square measurements.

Linear is one dimension, where as square measurements are 2 dimensional, meaning that you'd generally need two lengths to calculate an area (unless talking curved such as circle).

If you said millimetres squared to make a square meter, the answer would be 1,000,000. This seems counterintuitive because there are 1000mm in a meter, but as the difference is squared (length x length = area in squaring), it becomes 1,000x1,000