The game is mainly for primary school grade two，corresponding the second grade seventh unit of
primary school mathematics of Human education--Addition and subtraction of number.Imagine all
kinds of the wonderful worlds？Now，lets go！The little duck builds a tall building from here and now.
There are numbers on the floor.Cute little black head from outside the building to complete a formula.
Choose the correct answer on the floor of the crane can continue to increase the floor and come to
all kinds of wonderful worlds,fantastic ocean,fruit world,cake Kingdom......
QD learn aims at teaching through lively activities and happy learning.