randRange( 1, 9 )
randRange( 1, 9 )
randRange( 1, 9 )
randRange( 0, 8 )
1000 * A_1000 + 100 * A_100 + 10 * A_10 + A_1
randRange( 0, A_1000 - 1 )
randRange( 0, A_100 - 1 )
randRange( 0, A_10 - 1 )
randRange( A_1 + 1, 9 )
1000 * B_1000 + 100 * B_100 + 10 * B_10 + B_1
[]
graph.subtractor = new Subtractor( A, B );
graph.subtractor.show();
DUMMY = Array( graph.subtractor.getNumHints() );
A - B
graph.subtractor.showHint();