3.....8...24 5...5...25
3....9....27 4....7...28
11...3...31 5...6...30
4....9...36 4....8...32
11...4..44 12...4...48
5...8..40 6...7...42
3✘7=21 3✘8=24 3✘9=27 4✘5=20 4✘9=36 5✘6=30 6✘6=36 4✘8=32 5✘8=40 7✘7=49 6✘7=42 5✘9=45 注✘为乘号
(1)4X5=20
4X6=24
5X5=25
7X4=28
(2)5X6=30
4X8=32
5X7=35
6X6=36
(3)8X5=40
6X7=42
9X5=45
8X6=48