4个2相加                                            2×4=8

6+6+6                       4×2                  5乘4

4 + 4+4 +4 +4           6×3                 乘数是6和3

3+3+3+3+3+3           5×4                 2+2+2+2

5 +5 + 5 +5                                        3×6

2乘4                                                    4×5