Educational tools are provided that can include a plurality of sets of
placards with individual ones of these sets can include a plurality of
individual placards, and individual placards within the sets having
substantially the same surface area and can be associated with a common
symbol. The educational tool can also include at least two of the sets
including placards having different surface areas associated with
different symbols. Educational methods are also provided that include
providing a first set of placards, with the first set of placards
including individual placards having a first surface area associated with
a first symbol, and providing a second set of placards, with the second
set of placards including individual placards having a second surface
area associated with a second symbol.