50% of 20 =
                   ( 10 )

30% of 70 =
                   (       )

40% of 20 =
                   (       )

80% of 70 =
                   (       )

30% of 20 =
                   (       )

40% of 80 =
                   (       )

50% of 40 =
                   (       )

90% of 90 =
                   (       )

50% of 30 =
                   (       )

          +[         ]

30% of 50 =
                   ( 15 )

40% of 10 =
                   (       )

90% of 60 =
                   (       )

60% of 40 =
                   (       )

50% of 70 =
                   (       )

60% of 20 =
                   (       )

10% of 70 =
                   (       )

50% of 10 =
                   (       )

60% of 70 =
                   (       )

          +[         ]

70% of 40 =
                   ( 28 )

20% of 90 =
                   (       )

60% of 20 =
                   (       )

50% of 50 =
                   (       )

80% of 40 =
                   (       )

10% of 60 =
                   (       )

80% of 30 =
                   (       )

60% of 70 =
                   (       )

70% of 30 =
                   (       )

          +[         ]

       ++[[            ]]