Calculates the array product of two arrays (matrix multiplication). The number of columns for array 1 must match the number of rows for array 2. The square array has an equal number of rows and columns.
Array at first place represents the first array used in the array product.
Array at second place represents the second array.
More explanations on top of this page.
Choose the MMULT function. Select the first Array, then select the second Array. Using Function Wizard, mark the Array check box. Click OK. The current cell will be the top left corner of the output array.