Given three grids with each grid representing one whole.
Each grid represents 1 ones and each vertical bar of a grid represent 1 tenth.
There are 10 vertical bars in each grid, hence each grid represent 1 ones = 10 tenths and 2 grids represent 2 ones = 20 tenths.
Therefore, two complete grids are to be shaded to show that 2 ones is the same as 20 tenths