Explanation:
Draw out a 10 squares.
Shade in 4 of them to represent 4/10 = 0.40 = 0.4
Then use another color to shade another 4 squares. You should have 4+4 = 8 squares shaded, out of 10 total, giving 8/10 = 0.80 = 0.8
This is one visual way to see how 0.4 x 2 = 0.8
In other words, 0.4 x 2 means we have two copies of 0.4 added together. You could write it as 0.4 x 2 = 0.4 + 0.4 = 0.8 if you wanted.
See the diagram below.
