Annie and Jimmy each receive one dollar and six cents from the proceeds of Piper's shirt-laundering scheme. Piper herself takes one dollar and eight cents; after dividing the money three ways, there are two cents left over, and Piper makes sure to claim them for herself.
Piper has concocted a scheme in which classmates would give her a nickel apiece to have their shirts laundered by famous criminals on Alcatraz. In all, she has collected three dollars and twenty cents, and, since Annie and Jimmy have helped her with the logistics of the plan, she splits the money with them, three ways. Natalie, who has an uncanny ability with numbers, calculates how much each person should get instantaneously in her head. She then carefully counts out the money, giving each person their fair share.
In 1935, when the story takes place, one dollar and six cents is actually a good amount of money. Annie and Jimmy, in discussing what they will use their money for, conclude that a single share would buy "a whole Italian dinner in North Beach plus a double feature at the movies or a month of swims at Fleishhaker's Pool or a bunch of rides on the streetcars." Clearly, Piper's scheme has yielded lucrative results for the children.