300
                                40 = (-20)+(-10)=-20 + (-10)= -30
                40-(-30)
                 = 10
The amount left over is 10 tinker bell toys.
                                TINKER BELL there was 40 tinker bell toys.Two hours later, there were only 20, and an hour later, there was only 10.Write an addition sentence to describe this situation.Find the sum and explain its' meaning?