How do you use a hundred grid to model decimal multiplication?

A hundred grid can be used to model decimal multiplication by representing the values of the decimals as fractions of the grid. For example, if multiplying 0.3 by 0.4, you can shade 30 squares (representing 0.3) in one row and then 40 squares (representing 0.4) in the column intersecting those squares. The overlapping shaded area represents the product, which corresponds to the total area representing 0.12 or 12 squares in the grid. This visual approach helps in understanding how decimal values interact in multiplication.